Sorting algorithms/Gnome sort: Difference between revisions

Sorting algorithms/Gnome sort
You are encouraged to solve this task according to the task description, using any language you may know.

Sorting Algorithm
This is a sorting algorithm.   It may be applied to a set of data in order to sort it.     For comparing various sorts, see compare sorts.   For other sorting algorithms,   see sorting algorithms,   or:

O(n logn) sorts

O(n log2n) sorts
Shell Sort

 This page uses content from Wikipedia. The original article was at Gnome sort. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)

Gnome sort is a sorting algorithm which is similar to Insertion sort, except that moving an element to its proper place is accomplished by a series of swaps, as in Bubble Sort.

The pseudocode for the algorithm is:

function gnomeSort(a[0..size-1])
i := 1
j := 2
while i < size do
if a[i-1] <= a[i] then
// for descending sort, use >= for comparison
i := j
j := j + 1
else
swap a[i-1] and a[i]
i := i - 1
if i = 0 then
i := j
j := j + 1
endif
endif
done

Task

Implement the Gnome sort in your language to sort an array (or list) of numbers.

11l

Translation of: Python
F gnomesort(&a)
V i = 1
V j = 2
L i < a.len
I a[i - 1] <= a[i]
i = j
j++
E
swap(&a[i - 1], &a[i])
i--
I i == 0
i = j
j++
R a

print(gnomesort(&[3, 4, 2, 5, 1, 6]))
Output:
[1, 2, 3, 4, 5, 6]

360 Assembly

*        Gnome sort - Array base 0 - 15/04/2020
GNOME    CSECT
USING  GNOME,R13          base register
B      72(R15)            skip savearea
DC     17F'0'             savearea
SAVE   (14,12)            save previous context
ST     R13,4(R15)         link backward
ST     R15,8(R13)         link forward
LR     R13,R15            set addressability
LA     R6,1               i=1
LA     R7,2               j=2
DO WHILE=(C,R6,LT,NN)       while i<nn
LR     R1,R6                i
SLA    R1,2                 ~
LA     R8,TT-4(R1)          @tt(i-1)
LA     R9,TT(R1)            @tt(i)
L      R2,0(R8)             tt(i-1)
IF     C,R2,LE,0(R9) THEN     if tt(i-1)<=tt(i) then
LR     R6,R7                  i=j
LA     R7,1(R7)               j=j+1
ELSE     ,                    else
L      R4,0(R8)               t=tt(i-1)
L      R3,0(R9)               tt(i)
ST     R3,0(R8)               tt(i-1)=tt(i)
ST     R4,0(R9)               tt(i)=t
BCTR   R6,0                   i=i-1
IF   LTR,R6,Z,R6 THEN           if i=0 then
LR     R6,R7                    i=j
LA     R7,1(R7)                 j=j+1
ENDIF    ,                      endif
ENDIF    ,                    endif
ENDDO    ,                  endwhile
LA     R10,PG             @buffer
LA     R7,TT              @tt
LA     R6,1               i=1
DO WHILE=(C,R6,LE,NN)       do i=1 to nn
L      R2,0(R7)             tt(i)
XDECO  R2,XDEC              edit tt(i)
MVC    0(5,R10),XDEC+7      output tt(i)
LA     R10,5(R10)           @buffer
LA     R7,4(R7)             @tt++
LA     R6,1(R6)             i++
ENDDO    ,                  enddo i
XPRNT  PG,L'PG            print buffer
L      R13,4(0,R13)       restore previous savearea pointer
RETURN (14,12),RC=0       restore registers from calling save
TT       DC     F'557',F'5143',F'5432',F'6798',F'2874'
DC     F'3499',F'6949',F'4992',F'2555',F'4175'
DC     F'8264',F'3522',F'2045',F'2963',F'2625'
DC     F'-764',F'1845',F'1485',F'5792',F'7562'
DC     F'5044',F'3598',F'6817',F'4891',F'4350'
NN       DC     A((NN-TT)/L'TT)    number of items of tt
XDEC     DS     CL12               temp for xdeco
PG       DC     CL125' '           buffer
REGEQU
END    GNOME
Output:
-764  557 1485 1845 2045 2555 2625 2874 2963 3499 3522 3598 4175 4350 4891 4992 5044 5143 5432 5792 6798 6817 6949 7562 8264

AArch64 Assembly

Works with: as version Raspberry Pi 3B version Buster 64 bits
/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program gnomeSort64.s  */

/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeConstantesARM64.inc"

/*********************************/
/* Initialized data              */
/*********************************/
.data
szMessSortOk:       .asciz "Table sorted.\n"
szMessSortNok:      .asciz "Table not sorted !!!!!.\n"
sMessResult:        .asciz "Value  : @ \n"
szCarriageReturn:   .asciz "\n"

.align 4
TableNumber:      .quad   1,3,6,2,5,9,10,8,4,7
#TableNumber:     .quad   10,9,8,7,6,-5,4,3,2,1
.equ NBELEMENTS, (. - TableNumber) / 8
/*********************************/
/* UnInitialized data            */
/*********************************/
.bss
sZoneConv:       .skip 24
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main
main:                                              // entry of program
ldr x0,qAdrTableNumber                         // address number table
mov x1,0                                       // first element
mov x2,NBELEMENTS                              // number of élements
bl gnomeSort
ldr x0,qAdrTableNumber                         // address number table
bl displayTable

ldr x0,qAdrTableNumber                         // address number table
mov x1,NBELEMENTS                              // number of élements
bl isSorted                                    // control sort
cmp x0,1                                       // sorted ?
beq 1f
ldr x0,qAdrszMessSortNok                       // no !! error sort
bl affichageMess
b 100f
1:                                                 // yes
ldr x0,qAdrszMessSortOk
bl affichageMess
100:                                               // standard end of the program
mov x0,0                                       // return code
mov x8,EXIT                                    // request to exit program
svc 0                                          // perform the system call

qAdrsZoneConv:            .quad sZoneConv
qAdrszCarriageReturn:     .quad szCarriageReturn
qAdrsMessResult:          .quad sMessResult
qAdrTableNumber:          .quad TableNumber
qAdrszMessSortOk:         .quad szMessSortOk
qAdrszMessSortNok:        .quad szMessSortNok
/******************************************************************/
/*     control sorted table                                   */
/******************************************************************/
/* x0 contains the address of table */
/* x1 contains the number of elements  > 0  */
/* x0 return 0  if not sorted   1  if sorted */
isSorted:
stp x2,lr,[sp,-16]!              // save  registers
stp x3,x4,[sp,-16]!              // save  registers
mov x2,0
ldr x4,[x0,x2,lsl 3]
1:
add x2,x2,1
cmp x2,x1
bge 99f
ldr x3,[x0,x2, lsl 3]
cmp x3,x4
blt 98f
mov x4,x3
b 1b
98:
mov x0,0                       // not sorted
b 100f
99:
mov x0,1                       // sorted
100:
ldp x3,x4,[sp],16              // restaur  2 registers
ldp x2,lr,[sp],16              // restaur  2 registers
ret                            // return to address lr x30
/******************************************************************/
/*         gnome sort                                              */
/******************************************************************/
/* x0 contains the address of table */
/* x1 contains the first element    */
/* x2 contains the number of element */
gnomeSort:
stp x1,lr,[sp,-16]!        // save  registers
stp x2,x3,[sp,-16]!        // save  registers
stp x4,x5,[sp,-16]!        // save  registers
stp x6,x7,[sp,-16]!        // save  registers
stp x8,x9,[sp,-16]!        // save  registers
sub x2,x2,1                // compute end index n - 1
add x3,x1,1                // index i
add x7,x1,2                // index j
1:                             // start loop 1
cmp x3,x2
bgt 100f
sub x4,x3,1                //
ldr x5,[x0,x3,lsl 3]       // load value A[j]
ldr x6,[x0,x4,lsl 3]       // load value A[j+1]
cmp x5,x6                  // compare value
bge 2f
str x6,[x0,x3,lsl 3]       // if smaller inversion
str x5,[x0,x4,lsl 3]
sub x3,x3,1                // i = i - 1
cmp x3,x1
bne 1b                     // loop 1
2:
mov x3,x7                  // i = j
add x7,x7,1                // j = j + 1
b 1b                       // loop 1

100:
ldp x8,x9,[sp],16          // restaur  2 registers
ldp x6,x7,[sp],16          // restaur  2 registers
ldp x4,x5,[sp],16          // restaur  2 registers
ldp x2,x3,[sp],16          // restaur  2 registers
ldp x1,lr,[sp],16          // restaur  2 registers
ret                        // return to address lr x30

/******************************************************************/
/*      Display table elements                                */
/******************************************************************/
/* x0 contains the address of table */
displayTable:
stp x1,lr,[sp,-16]!              // save  registers
stp x2,x3,[sp,-16]!              // save  registers
mov x2,x0                        // table address
mov x3,0
1:                                   // loop display table
ldr x0,[x2,x3,lsl 3]
ldr x1,qAdrsZoneConv
bl conversion10S                  // décimal conversion
ldr x0,qAdrsMessResult
ldr x1,qAdrsZoneConv
bl strInsertAtCharInc            // insert result at @ character
bl affichageMess                 // display message
add x3,x3,1
cmp x3,NBELEMENTS - 1
ble 1b
ldr x0,qAdrszCarriageReturn
bl affichageMess
mov x0,x2
100:
ldp x2,x3,[sp],16               // restaur  2 registers
ldp x1,lr,[sp],16               // restaur  2 registers
ret                             // return to address lr x30
/********************************************************/
/*        File Include fonctions                        */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"

Action!

PROC PrintArray(INT ARRAY a INT size)
INT i

Put('[)
FOR i=0 TO size-1
DO
IF i>0 THEN Put(' ) FI
PrintI(a(i))
OD
Put(']) PutE()
RETURN

PROC GnomeSort(INT ARRAY a INT size)
INT i,j,tmp

i=1 j=2
WHILE i<size
DO
IF a(i-1)<=a(i) THEN
i=j j==+1
ELSE
tmp=a(i-1) a(i-1)=a(i) a(i)=tmp
i==-1
IF i=0 THEN
i=j j==+1
FI
FI
OD
RETURN

PROC Test(INT ARRAY a INT size)
PrintE("Array before sort:")
PrintArray(a,size)
GnomeSort(a,size)
PrintE("Array after sort:")
PrintArray(a,size)
PutE()
RETURN

PROC Main()
INT ARRAY
a(10)=[1 4 65535 0 3 7 4 8 20 65530],
b(21)=[10 9 8 7 6 5 4 3 2 1 0
65535 65534 65533 65532 65531
65530 65529 65528 65527 65526],
c(8)=[101 102 103 104 105 106 107 108],
d(12)=[1 65535 1 65535 1 65535 1
65535 1 65535 1 65535]

Test(a,10)
Test(b,21)
Test(c,8)
Test(d,12)
RETURN
Output:
Array before sort:
[1 4 -1 0 3 7 4 8 20 -6]
Array after sort:
[-6 -1 0 1 3 4 4 7 8 20]

Array before sort:
[10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10]
Array after sort:
[-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10]

Array before sort:
[101 102 103 104 105 106 107 108]
Array after sort:
[101 102 103 104 105 106 107 108]

Array before sort:
[1 -1 1 -1 1 -1 1 -1 1 -1 1 -1]
Array after sort:
[-1 -1 -1 -1 -1 -1 1 1 1 1 1 1]

ActionScript

function gnomeSort(array:Array)
{
var pos:uint = 0;
while(pos < array.length)
{
if(pos == 0 || array[pos] >= array[pos-1])
pos++;
else
{
var tmp = array[pos];
array[pos] = array[pos-1];
array[pos-1] = tmp;
pos--;
}
}
return array;
}

Ada

This example is a generic procedure for constrained array types.

generic
type Element_Type is private;
type Index is (<>);
type Collection is array(Index) of Element_Type;
with function "<=" (Left, Right : Element_Type) return Boolean is <>;
procedure Gnome_Sort(Item : in out Collection);
procedure Gnome_Sort(Item : in out Collection) is
procedure Swap(Left, Right : in out Element_Type) is
Temp : Element_Type := Left;
begin
Left := Right;
Right := Temp;
end Swap;

I : Integer := Index'Pos(Index'Succ(Index'First));
J : Integer := I + 1;
begin
while I <= Index'Pos(Index'Last) loop
if Item(Index'Val(I - 1)) <= Item(Index'Val(I)) then
I := J;
J := J + 1;
else
Swap(Item(Index'Val(I - 1)), Item(Index'Val(I)));
I := I - 1;
if I = Index'Pos(Index'First) then
I := J;
J := J + 1;
end if;
end if;
end loop;
end Gnome_Sort;

Usage example:

with Gnome_Sort;
with Ada.Text_Io; use Ada.Text_Io;

procedure Gnome_Sort_Test is
type Index is range 0..9;
type Buf is array(Index) of Integer;
procedure Sort is new Gnome_Sort(Integer, Index, Buf);
A : Buf := (900, 700, 800, 600, 400, 500, 200, 100, 300, 0);
begin
for I in A'range loop
Put(Integer'Image(A(I)));
end loop;
New_Line;
Sort(A);
for I in A'range loop
Put(Integer'Image(A(I)));
end loop;
New_Line;
end Gnome_Sort_Test;

ALGOL 68

Works with: ALGOL 68 version Standard - no extensions to language used
Works with: ALGOL 68G version Any - tested with release mk15-0.8b.fc9.i386
Works with: ELLA ALGOL 68 version Any (with appropriate job cards AND formatted transput statements removed) - tested with release 1.8.8d.fc9.i386
MODE SORTSTRUCT = INT;

PROC inplace gnome sort = (REF[]SORTSTRUCT list)REF[]SORTSTRUCT:
BEGIN
INT i:=LWB list + 1, j:=LWB list + 2;
WHILE i <= UPB list DO
IF list[i-1] <= list[i] THEN
i := j; j+:=1
ELSE
SORTSTRUCT swap = list[i-1]; list[i-1]:= list[i]; list[i]:= swap;
i-:=1;
IF i=LWB list THEN i:=j; j+:=1 FI
FI
OD;
list
END;

PROC gnome sort = ([]SORTSTRUCT seq)[]SORTSTRUCT:
in place gnome sort(LOC[LWB seq: UPB seq]SORTSTRUCT:=seq);

[]SORTSTRUCT unsorted array data = ( -40, 77, 9, 0, 2, 1, 0, 1701 );
print((gnome sort(unsorted array data), new line))

Output:

-40         +0         +0         +1         +2         +9        +77      +1701

ALGOL W

begin % gnome sort %

% gnome sorts in-place a, a must have bounds 1 :: size %
procedure gnomeSort( integer array a ( * ); integer value size ) ;
begin
integer i, j;
i := 2;
j := 3;
while i <= size do begin
if a( i - 1 ) <= a( i ) then begin
i := j;
j := j + 1
end
else begin
integer swap;
swap       := a( i - 1 );
a( i - 1 ) := a( i     );
a( i     ) := swap;
i          := i - 1;
if i = 1 then begin
i := j;
j := j + 1
end if_i_eq_1
end if_a_i_minus_1_le_a_i__
end while_i_lt_size
end gnomeSort ;

begin % test gnomeSort %
integer array numbers ( 1 :: 11 );
integer nPos;
% constructy an array of integers and sort it %
nPos := 1;
for v := 4, 65, 2, 31, 0, 99, 2, 8, 3, 782, 1 do begin
numbers( nPos ) := v;
nPos            := nPos + 1
end for_v ;
gnomeSort( numbers, 11 );
% print the sorted array %
for n := 1 until 11 do writeon( i_w := 1, s_w := 0, " ", numbers( n ) )
end tests
end.
Output:
0 1 2 2 3 4 8 31 65 99 782

ARM Assembly

Works with: as version Raspberry Pi
/* ARM assembly Raspberry PI  */
/*  program gnomeSort.s  */

/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly
for the routine affichageMess conversion10
see at end of this program the instruction include */
/* for constantes see task include a file in arm assembly */
/************************************/
/* Constantes                       */
/************************************/
.include "../constantes.inc"

/*********************************/
/* Initialized data              */
/*********************************/
.data
szMessSortOk:       .asciz "Table sorted.\n"
szMessSortNok:      .asciz "Table not sorted !!!!!.\n"
sMessResult:        .asciz "Value  : @ \n"
szCarriageReturn:   .asciz "\n"

.align 4
#TableNumber:      .int   1,3,6,2,5,9,10,8,4,7
TableNumber:       .int   10,9,8,7,6,5,4,3,2,1
.equ NBELEMENTS, (. - TableNumber) / 4
/*********************************/
/* UnInitialized data            */
/*********************************/
.bss
sZoneConv:            .skip 24
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main
main:                                              @ entry of program

ldr r0,iAdrTableNumber                         @ address number table
mov r1,#0                                      @ first element
mov r2,#NBELEMENTS                             @ number of élements
bl gnomeSort
ldr r0,iAdrTableNumber                         @ address number table
bl displayTable

ldr r0,iAdrTableNumber                         @ address number table
mov r1,#NBELEMENTS                             @ number of élements
bl isSorted                                    @ control sort
cmp r0,#1                                      @ sorted ?
beq 1f
ldr r0,iAdrszMessSortNok                       @ no !! error sort
bl affichageMess
b 100f
1:                                                 @ yes
ldr r0,iAdrszMessSortOk
bl affichageMess
100:                                               @ standard end of the program
mov r0, #0                                     @ return code
mov r7, #EXIT                                  @ request to exit program
svc #0                                         @ perform the system call

iAdrszCarriageReturn:     .int szCarriageReturn
iAdrsMessResult:          .int sMessResult
iAdrTableNumber:          .int TableNumber
iAdrszMessSortOk:         .int szMessSortOk
iAdrszMessSortNok:        .int szMessSortNok
/******************************************************************/
/*     control sorted table                                   */
/******************************************************************/
/* r0 contains the address of table */
/* r1 contains the number of elements  > 0  */
/* r0 return 0  if not sorted   1  if sorted */
isSorted:
push {r2-r4,lr}                                    @ save registers
mov r2,#0
ldr r4,[r0,r2,lsl #2]
1:
add r2,#1
cmp r2,r1
movge r0,#1
bge 100f
ldr r3,[r0,r2, lsl #2]
cmp r3,r4
movlt r0,#0
blt 100f
mov r4,r3
b 1b
100:
pop {r2-r4,lr}
bx lr                                              @ return
/******************************************************************/
/*         gnome Sort                                          */
/******************************************************************/
/* r0 contains the address of table */
/* r1 contains the first element    */
/* r2 contains the number of element */
gnomeSort:
push {r1-r9,lr}           @ save registers
sub r2,r2,#1              @ compute end index = n - 1
add r3,r1,#1              @ index i
add r7,r1,#2              @ j
1:                            @ start loop 1
cmp r3,r2
bgt 100f
sub r4,r3,#1
ldr r5,[r0,r3,lsl #2]     @ load value A[j]
ldr r6,[r0,r4,lsl #2]     @ load value A[j-1]
cmp r5,r6                 @ compare value
bge 2f
str r6,[r0,r3,lsl #2]     @ if smaller inversion
str r5,[r0,r4,lsl #2]
sub r3,r3,#1             @ i = i - 1
cmp r3,r1
moveq r3,r7               @ if i = 0  i = j
addeq r7,r7,#1            @ if i = 0  j = j+1
b 1b                      @ loop 1
2:
mov r3,r7                 @ i = j
add r7,r7,#1              @ j = j + 1
b 1b                      @ loop 1

100:
pop {r1-r9,lr}
bx lr                                                  @ return

/******************************************************************/
/*      Display table elements                                */
/******************************************************************/
/* r0 contains the address of table */
displayTable:
push {r0-r3,lr}                                    @ save registers
mov r2,r0                                          @ table address
mov r3,#0
1:                                                     @ loop display table
ldr r0,[r2,r3,lsl #2]
ldr r1,iAdrsZoneConv                               @
bl conversion10S                                    @ décimal conversion
ldr r0,iAdrsMessResult
ldr r1,iAdrsZoneConv                               @ insert conversion
bl strInsertAtCharInc
bl affichageMess                                   @ display message
add r3,#1
cmp r3,#NBELEMENTS - 1
ble 1b
ldr r0,iAdrszCarriageReturn
bl affichageMess
mov r0,r2
100:
pop {r0-r3,lr}
bx lr
iAdrsZoneConv:           .int sZoneConv
/***************************************************/
/*      ROUTINES INCLUDE                           */
/***************************************************/
.include "../affichage.inc"

Arturo

gnomeSort: function [items][
i: 1
j: 2
arr: new items
while [i < size arr][
if? arr\[i-1] =< arr\[i] [
i: j
j: j + 1
]
else [
tmp: arr\[i]
arr\[i]: arr\[i-1]
arr\[i-1]: tmp

i: i-1
if i=0 [
i: j
j: j + 1
]
]
]
return arr
]

print gnomeSort [3 1 2 8 5 7 9 4 6]
Output:
1 2 3 4 5 6 7 8 9

AutoHotkey

contributed by Laszlo on the ahk forum

MsgBox % GnomeSort("")
MsgBox % GnomeSort("xxx")
MsgBox % GnomeSort("3,2,1")
MsgBox % GnomeSort("dog,000000,xx,cat,pile,abcde,1,cat,zz,xx,z")

GnomeSort(var) {                         ; SORT COMMA SEPARATED LIST
StringSplit a, var, `,                ; make array, size = a0
i := 2, j := 3
While i <= a0 {                       ; stop when sorted
u := i-1
If (a%u% < a%i%)                   ; search for pairs to swap
i := j, j := j+1
Else {                             ; swap
t := a%u%, a%u% := a%i%, a%i% := t
If (--i = 1)                    ; restart search
i := j, j++
}
}
Loop % a0                             ; construct string from sorted array
sorted .= "," . a%A_Index%
Return SubStr(sorted,2)               ; drop leading comma
}

AWK

AWK arrays can be passed as parameters, but not returned, so they are usually global.

This version includes the mark/resume optimization. It remembers where it was before backing up so that once an item is backed up to its proper place the process resumes from where it was before backing up.

#!/usr/bin/awk -f

BEGIN {
d[1] = 3.0
d[2] = 4.0
d[3] = 1.0
d[4] = -8.4
d[5] = 7.2
d[6] = 4.0
d[7] = 1.0
d[8] = 1.2
showD("Before: ")
gnomeSortD()
showD("Sorted: ")
exit
}

function gnomeSortD(    i) {
for (i = 2; i <= length(d); i++) {
if (d[i] < d[i-1]) gnomeSortBackD(i)
}
}

function gnomeSortBackD(i,     t) {
for (; i > 1 && d[i] < d[i-1]; i--) {
t = d[i]
d[i] = d[i-1]
d[i-1] = t
}
}

function showD(p,   i) {
printf p
for (i = 1; i <= length(d); i++) {
printf d[i] " "
}
print ""
}

Example output:

Before: 3 4 1 -8.4 7.2 4 1 1.2
Sorted: -8.4 1 1 1.2 3 4 4 7.2

BASIC

Works with: QuickBasic version 4.5
Translation of: C
dim a(0 to n-1) as integer
'...more code...
sort:
i = 1
j = 2

while(i < ubound(a) - lbound(a))
if a(i-1) <= a(i) then
i = j
j = j + 1
else
swap a(i-1), a(i)
i = i - 1
if i = 0 then
i = j
j = j + 1
end if
end if
wend

Batch File

Works with: Windows NT
@ECHO OFF
SETLOCAL EnableExtensions EnableDelayedExpansion
:: GnomeSort.cmd in WinNT Batch using pseudo array.
:: Set the number of random elements to sort.
SET numElements=100
:: Decrement numElements for use in zero-based loops as in (0, 1, %numElements% - 1).
SET /A tmpElements=%numElements% - 1

:: Create array of random numbers and output to file.
ECHO GnomeSort Random Input 0 to %tmpElements%:>%~n0.txt
FOR /L %%X IN (0, 1, %tmpElements%) DO (
SET array[%%X]=!RANDOM!
ECHO !array[%%X]!>>%~n0.txt
)

:GnomeSort
:: Initialize the pointers i-1, i, and j.
SET gs1=0
SET gs2=1
SET gs3=2
:GS_Loop
:: Implementing a WHILE loop in WinNT batch using GOTO. It only executes
:: if the condition is true and continues until the condition is false.
:: First, display [i-1][j - 2] to the Title Bar.
SET /A gsTmp=%gs3% - 2
TITLE GnomeSort:[%gs1%][%gsTmp%] of %tmpElements%
:: ...then start Main Loop. It's a direct implementation of the
:: pseudo code supplied by Rosetta Code. I had to add an additional
:: pointer to represent i-1, because of limitations in WinNT Batch.
IF %gs2% LSS %numElements% (
REM if i-1 <= i advance pointers to next unchecked element, then loop.
IF !array[%gs1%]! LEQ !array[%gs2%]! (
SET /A gs1=%gs3% - 1
SET /A gs2=%gs3%
SET /A gs3=%gs3% + 1
) ELSE (
REM ... else swap i-1 and i, decrement pointers to check previous element, then loop.
SET gsTmp=!array[%gs1%]!
SET array[%gs1%]=!array[%gs2%]!
SET array[%gs2%]=!gsTmp!
SET /A gs1-=1
SET /A gs2-=1
REM if first element has been reached, set pointers to next unchecked element.
IF !gs2! EQU 0 (
SET /A gs1=%gs3% - 1
SET /A gs2=%gs3%
SET /A gs3=%gs3% + 1
)
)
GOTO :GS_Loop
)
TITLE GnomeSort:[%gs1%][%gsTmp%] - Done!

:: write sorted elements out to file
ECHO.>>%~n0.txt
ECHO GnomeSort Sorted Output 0 to %tmpElements%:>>%~n0.txt
FOR /L %%X IN (0, 1, %tmpElements%) DO ECHO !array[%%X]!>>%~n0.txt

ENDLOCAL
EXIT /B 0

BBC BASIC

DEF PROC_GnomeSort1(Size%)
I%=2
J%=2
REPEAT
IF data%(J%-1) <=data%(J%) THEN
I%+=1
J%=I%
ELSE
SWAP data%(J%-1),data%(J%)
J%-=1
IF J%=1 THEN
I%+=1
J%=I%
ENDIF
ENDIF
UNTIL I%>Size%
ENDPROC

BCPL

get "libhdr"

let gnomesort(A, len) be
\$(  let i=1 and j=2 and t=?
while i < len
test A!(i-1) <= A!i
\$(  i := j
j := j + 1
\$)
or
\$(  t := A!(i-1)
A!(i-1) := a!i
A!i := t
i := i - 1
if i = 0
\$(  i := j
j := j + 1
\$)
\$)
\$)

let writearray(A, len) be
for i=0 to len-1 do
writed(A!i, 6)

let start() be
\$(  let array = table 52, -5, -20, 199, 65, -3, 190, 25, 9999, -5342
let length = 10

writes("Input:  ") ; writearray(array, length) ; wrch('*N')
gnomesort(array, length)
writes("Output: ") ; writearray(array, length) ; wrch('*N')
\$)
Output:
Input:      52    -5   -20   199    65    -3   190    25  9999 -5342
Output:  -5342   -20    -5    -3    25    52    65   190   199  9999

C

This algorithm sorts in place modifying the passed array (of n integer numbers).

void gnome_sort(int *a, int n)
{
int i=1, j=2, t;
# define swap(i, j) { t = a[i]; a[i] = a[j]; a[j] = t; }
while(i < n) {
if (a[i - 1] > a[i]) {
swap(i - 1, i);
if (--i) continue;
}
i = j++;
}
# undef swap
}

C#

public static void gnomeSort(int[] anArray)
{
int first = 1;
int second = 2;

while (first < anArray.Length)
{
if (anArray[first - 1] <= anArray[first])
{
first = second;
second++;
}
else
{
int tmp = anArray[first - 1];
anArray[first - 1] = anArray[first];
anArray[first] = tmp;
first -= 1;
if (first == 0)
{
first = 1;
second = 2;
}
}

}
}

C++

Uses C++11. Compile with

g++ -std=c++11 gnome.cpp
#include <algorithm>
#include <iterator>
#include <iostream>

template<typename RandomAccessIterator>
void gnome_sort(RandomAccessIterator begin, RandomAccessIterator end) {
auto i = begin + 1;
auto j = begin + 2;

while (i < end) {
if (!(*i < *(i - 1))) {
i = j;
++j;
} else {
std::iter_swap(i - 1, i);
--i;
if (i == begin) {
i = j;
++j;
}
}
}
}

int main() {
int a[] = {100, 2, 56, 200, -52, 3, 99, 33, 177, -199};
gnome_sort(std::begin(a), std::end(a));
copy(std::begin(a), std::end(a), std::ostream_iterator<int>(std::cout, " "));
std::cout << "\n";
}

Output:

-199 -52 2 3 33 56 99 100 177 200

Clojure

Translation of: Haskell
(defn gnomesort
([c] (gnomesort c <))
([c pred]
(loop [x [] [y1 & ys :as y] (seq c)]
(cond (empty? y) x
(empty? x) (recur (list y1) ys)
true (let [zx (last x)]
(if (pred y1 zx)
(recur (butlast x) (concat (list y1 zx) ys))
(recur (concat x (list y1)) ys)))))))

(println (gnomesort [3 1 4 1 5 9 2 6 5]))

COBOL

Procedure division stuff only.

C-SORT SECTION.
C-000.
DISPLAY "SORT STARTING".

SET WB-IX-1 TO 2.
MOVE 1 TO WC-NEXT-POSN.

PERFORM E-GNOME UNTIL WC-NEXT-POSN > WC-SIZE.

DISPLAY "SORT FINISHED".

C-999.
EXIT.

E-GNOME SECTION.
E-000.
IF WB-ENTRY(WB-IX-1 - 1) NOT > WB-ENTRY(WB-IX-1)
ADD 1       TO WC-NEXT-POSN
SET WB-IX-1 TO WC-NEXT-POSN
ELSE
MOVE WB-ENTRY(WB-IX-1 - 1) TO WC-TEMP
MOVE WB-ENTRY(WB-IX-1)     TO WB-ENTRY(WB-IX-1 - 1)
MOVE WC-TEMP               TO WB-ENTRY(WB-IX-1)
SET WB-IX-1                DOWN BY 1
IF WB-IX-1 = 1
ADD 1       TO WC-NEXT-POSN
SET WB-IX-1 TO WC-NEXT-POSN.

E-999.
EXIT.

Common Lisp

(defun gnome-sort (array predicate &aux (length (length array)))
(do ((position (min 1 length)))
((eql length position) array)
(cond
((eql 0 position)
(incf position))
((funcall predicate
(aref array position)
(aref array (1- position)))
(rotatef (aref array position)
(aref array (1- position)))
(decf position))
(t (incf position)))))

D

import std.stdio, std.algorithm;

void gnomeSort(T)(T arr) {
int i = 1, j = 2;
while (i < arr.length) {
if (arr[i-1] <= arr[i]) {
i = j;
j++;
} else {
swap(arr[i-1], arr[i]);
i--;
if (i == 0) {
i = j;
j++;
}
}
}
}

void main() {
auto a = [3,4,2,5,1,6];
gnomeSort(a);
writeln(a);
}

Delphi

Dynamic array is a 0-based array of variable length

Static array is an arbitrary-based array of fixed length

program TestGnomeSort;

{\$APPTYPE CONSOLE}

{.\$DEFINE DYNARRAY}  // remove '.' to compile with dynamic array

type
TItem = Integer;   // declare ordinal type for array item
{\$IFDEF DYNARRAY}
TArray = array of TItem;          // dynamic array
{\$ELSE}
TArray = array[0..15] of TItem;   // static array
{\$ENDIF}

procedure GnomeSort(var A: TArray);
var
Item: TItem;
I, J: Integer;

begin
I:= Low(A) + 1;
J:= Low(A) + 2;
while I <= High(A) do begin
if A[I - 1] <= A[I] then begin
I:= J;
J:= J + 1;
end
else begin
Item:= A[I - 1];
A[I - 1]:= A[I];
A[I]:= Item;
I:= I - 1;
if I = Low(A) then begin
I:= J;
J:= J + 1;
end;
end;
end;
end;

var
A: TArray;
I: Integer;

begin
{\$IFDEF DYNARRAY}
SetLength(A, 16);
{\$ENDIF}
for I:= Low(A) to High(A) do
A[I]:= Random(100);
for I:= Low(A) to High(A) do
Write(A[I]:3);
Writeln;
GnomeSort(A);
for I:= Low(A) to High(A) do
Write(A[I]:3);
Writeln;
Readln;
end.

Output:

0  3 86 20 27 67 31 16 37 42  8 47  7 84  5 29
0  3  5  7  8 16 20 27 29 31 37 42 47 67 84 86

DWScript

procedure GnomeSort(a : array of Integer);
var
i, j : Integer;
begin
i := 1;
j := 2;
while i < a.Length do begin
if a[i-1] <= a[i] then begin
i := j;
j := j + 1;
end else begin
a.Swap(i-1, i);
i := i - 1;
if i = 0 then begin
i := j;
j := j + 1;
end;
end;
end;
end;

var i : Integer;
var a := new Integer[16];

Print('{');
for i := 0 to a.High do begin
a[i] := i xor 5;
Print(Format('%3d ', [a[i]]));
end;
PrintLn('}');

GnomeSort(a);

Print('{');
for i := 0 to a.High do
Print(Format('%3d ', [a[i]]));
PrintLn('}');

Ouput :

{  5   4   7   6   1   0   3   2  13  12  15  14   9   8  11  10 }
{  0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15 }

E

def gnomeSort(array) {
var size := array.size()
var i := 1
var j := 2
while (i < size) {
if (array[i-1] <= array[i]) {
i := j
j += 1
} else {
def t := array[i-1]
array[i-1] := array[i]
array[i] := t
i -= 1
if (i <=> 0) {
i := j
j += 1
}
}
}
}
? def a := [7,9,4,2,1,3,6,5,0,8].diverge()
# value: [7, 9, 4, 2, 1, 3, 6, 5, 0, 8].diverge()

? gnomeSort(a)
? a
# value: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9].diverge()

Eiffel

class
GNOME_SORT [G -> COMPARABLE]

feature

sort (ar: ARRAY [G]): ARRAY [G]
-- Sorted array in ascending order.
require
array_not_void: ar /= Void
local
i, j: INTEGER
ith: G
do
create Result.make_empty
Result.deep_copy (ar)
from
i := 2
j := 3
until
i > Result.count
loop
if Result [i - 1] <= Result [i] then
i := j
j := j + 1
else
ith := Result [i - 1]
Result [i - 1] := Result [i]
Result [i] := ith
i := i - 1
if i = 1 then
i := j
j := j + 1
end
end
end
ensure
Same_length: ar.count = Result.count
Result_is_sorted: is_sorted (Result)
end

feature {NONE}

is_sorted (ar: ARRAY [G]): BOOLEAN
--- Is 'ar' sorted in ascending order?
require
ar_not_empty: ar.is_empty = False
local
i: INTEGER
do
Result := True
from
i := ar.lower
until
i = ar.upper
loop
if ar [i] > ar [i + 1] then
Result := False
end
i := i + 1
end
end

end

Test:

class
APPLICATION

create
make

feature

make
do
test := <<7, 99, -7, 1, 0, 25, -10>>
io.put_string ("unsorted:%N")
across
test as ar
loop
io.put_string (ar.item.out + "%T")
end
io.new_line
io.put_string ("sorted:%N")
create gnome
test := gnome.sort (test)
across
test as ar
loop
io.put_string (ar.item.out + "%T")
end
end

test: ARRAY [INTEGER]

gnome: GNOME_SORT [INTEGER]

end
Output:
Unsorted:
7    99    -7    1    0    25    -10
Sorted:
-7    -10    0    1    7    25    99

Elena

ELENA 5.0 :

import extensions;
import system'routines;

extension op
{
gnomeSort()
{
var list := self.clone();
int i := 1;
int j := 2;

while (i < list.Length)
{
if (list[i-1]<=list[i])
{
i := j;
j += 1
}
else
{
list.exchange(i-1,i);
i -= 1;
if (i==0)
{
i := 1;
j := 2
}
}
};

^ list
}
}

public program()
{
var list := new int[]{3, 9, 4, 6, 8, 1, 7, 2, 5};

console.printLine("before:", list.asEnumerable());
console.printLine("after :", list.gnomeSort().asEnumerable())
}
Output:
before:3,9,4,6,8,1,7,2,5
after :1,2,3,4,5,6,7,8,9

Elixir

Translation of: Erlang
defmodule Sort do
def gnome_sort([]), do: []
def gnome_sort([h|t]), do: gnome_sort([h], t)

defp gnome_sort(list, []), do: list
defp gnome_sort([prev|p], [next|n]) when next > prev, do: gnome_sort(p, [next,prev|n])
defp gnome_sort(p, [next|n]), do: gnome_sort([next|p], n)
end

IO.inspect Sort.gnome_sort([8,3,9,1,3,2,6])
Output:
[1, 2, 3, 3, 6, 8, 9]

Erlang

-module(gnome_sort).
-export([gnome/1]).

gnome(L, []) -> L;
gnome([Prev|P], [Next|N]) when Next > Prev ->
gnome(P, [Next|[Prev|N]]);
gnome(P, [Next|N]) ->
gnome([Next|P], N).
gnome([H|T]) -> gnome([H], T).
Eshell V5.7.3  (abort with ^G)
1> c(gnome_sort).
{ok,gnome_sort}
2> gnome_sort:gnome([8,3,9,1,3,2,6]).
[1,2,3,3,6,8,9]
3>

Euphoria

function gnomeSort(sequence s)
integer i,j
object temp
i = 1
j = 2
while i < length(s) do
if compare(s[i], s[i+1]) <= 0 then
i = j
j += 1
else
temp = s[i]
s[i] = s[i+1]
s[i+1] = temp
i -= 1
if i = 0 then
i = j
j += 1
end if
end if
end while
return s
end function

F#

let inline gnomeSort (a: _ []) =
let rec loop i j =
if i < a.Length then
if a.[i-1] <= a.[i] then loop j (j+1) else
let t = a.[i-1]
a.[i-1] <- a.[i]
a.[i] <- t
if i=1 then loop j (j+1) else loop (i-1) j
loop 1 2

Factor

USING: kernel math sequences ;
IN: rosetta-code.gnome-sort

: inc-pos ( pos seq -- pos' seq )
[ 1 + ] dip ; inline

: dec-pos ( pos seq -- pos' seq )
[ 1 - ] dip ; inline

: take-two ( pos seq -- elt-at-pos-1 elt-at-pos )
[ dec-pos nth ] [ nth ] 2bi ; inline

: need-swap? ( pos seq -- pos seq ? )
over 1 < [ f ] [ 2dup take-two > ] if ;

: swap-back ( pos seq -- pos seq' )
[ take-two ] 2keep
[ dec-pos set-nth ] 2keep
[ set-nth ] 2keep ;

: gnome-sort ( seq -- sorted-seq )
1 swap [ 2dup length < ] [
2dup [ need-swap? ] [ swap-back dec-pos ] while
2drop inc-pos
] while nip ;

Example:

IN: scratchpad USE: rosetta-code.gnome-sort
Loading resource:extra/rosetta-code/gnome-sort/gnome-sort.factor
IN: scratchpad V{ 10 9 5 7 4 3 6 8 1 2 } gnome-sort .
V{ 1 2 3 4 5 6 7 8 9 10 }

Fantom

class Main
{
Int[] gnomesort (Int[] list)
{
i := 1
j := 2
while (i < list.size)
{
if (list[i-1] <= list[i])
{
i = j
j += 1
}
else
{
list.swap(i-1, i)
i -= 1
if (i == 0)
{
i = j
j += 1
}
}
}

return list
}

Void main ()
{
list := [4,1,5,8,2,1,5,7]
echo ("" + list + " sorted is " + gnomesort (list))
}
}

Output:

[4, 1, 5, 8, 2, 1, 5, 7] sorted is [1, 1, 2, 4, 5, 5, 7, 8]

Forth

defer precedes
defer exchange

: gnomesort                   ( a n)
swap >r 1                   ( n c)
begin                       ( n c)
over over >               ( n c f)
while                       ( n c)
dup if                    ( n c)
dup dup 1- over over r@ precedes
if r@ exchange 1- else drop drop 1+ then
else 1+ then              ( n c)
repeat drop drop r> drop    ( --)
;

create example
8 93 69 52 50 79 33 52 19 77 , , , , , , , , , ,

:noname >r cells r@ + @ swap cells r> + @ swap < ; is precedes
:noname >r cells r@ + swap cells r> + over @ over @ swap rot ! swap ! ; is exchange

: .array 10 0 do example i cells + ? loop cr ;

.array example 10 gnomesort .array

A slightly optimized version is presented below, where Gnome sort keeps track of its previous position. This reduces the number of iterations significantly.

: gnomesort+                           ( a n)
swap >r 2 tuck 1-                    ( c2 n c1)
begin                                ( c2 n c1)
over over >                        ( c2 n c1 f)
while                                ( c2 n c1)
dup if                             ( c2 n c1)
dup dup 1- over over r@ precedes
if r@ exchange 1- else drop drop drop >r dup 1+ swap r> swap then
else drop >r dup 1+ swap r> swap then
repeat drop drop drop r> drop
;                                      ( --)

Fortran

Works with: Fortran version 90 and later
program example

implicit none

integer :: array(8) = (/ 2, 8, 6, 1, 3, 5, 4, 7 /)

call Gnomesort(array)
write(*,*) array

contains

subroutine Gnomesort(a)

integer, intent(in out) :: a(:)
integer :: i, j, temp

i = 2
j = 3
do while (i <= size(a))
if (a(i-1) <= a(i)) then
i = j
j = j + 1
else
temp = a(i-1)
a(i-1) = a(i)
a(i) = temp
i = i -  1
if (i == 1) then
i = j
j = j + 1
end if
end if
end do

end subroutine Gnomesort

Optimized Version

SUBROUTINE OPTIMIZEDGNOMESORT(A)     ! Nice
IMPLICIT NONE
!
! Dummy arguments
!
REAL , DIMENSION(0:)  ::  A
INTENT (INOUT) A
!
! Local variables
!
INTEGER  ::  posy
!
DO posy = 1 , UBOUND(A , 1)       !size(a)-1
CALL GNOMESORT(A , posy)
END DO
RETURN
CONTAINS

SUBROUTINE GNOMESORT(A , Upperbound)
IMPLICIT NONE
!
! Dummy arguments
!
INTEGER  ::  Upperbound
REAL , DIMENSION(0:)  ::  A
INTENT (IN) Upperbound
INTENT (INOUT) A
!
! Local variables
!
LOGICAL  ::  eval
INTEGER  ::  posy
REAL  ::  t
!
eval = .FALSE.
posy = Upperbound
eval = (posy>0) .AND. (A(posy - 1)>A(posy))
!     do while ((posy > 0) .and. (a(posy-1) > a(posy)))
DO WHILE ( eval )
t = A(posy)
A(posy) = A(posy - 1)
A(posy - 1) = t
!
posy = posy - 1
eval = (posy>0)
IF( eval )THEN     ! Have to use as a guard condition
eval = (A(posy - 1)>A(posy))
ELSE
eval = .FALSE.
END IF
END DO
RETURN
END SUBROUTINE GNOMESORT

END SUBROUTINE OPTIMIZEDGNOMESORT
!

end program example

FreeBASIC

Used the task pseudo code as a base

' version 21-10-2016
' compile with: fbc -s console
' for boundry checks on array's compile with: fbc -s console -exx

Sub gnomesort(gnome() As Long)
' sort from lower bound to the highter bound
' array's can have subscript range from -2147483648 to +2147483647
Dim As Long lb = LBound(gnome)
Dim As Long ub = UBound(gnome)
Dim As Long i = lb +1, j = lb +2

While i < (ub +1)
' replace "<=" with ">=" for downwards sort
If gnome(i -1) <= gnome(i) Then
i = j
j += 1
Else
Swap gnome(i -1), gnome(i)
i -= 1
If i = lb Then
i = j
j += 1
End If
End If
Wend

End Sub

' ------=< MAIN >=------

Dim As Long i, array(-7 To 7)

Dim As Long a = LBound(array), b = UBound(array)

Randomize Timer
For i = a To b : array(i) = i  : Next
For i = a To b ' little shuffle
Swap array(i), array(Int(Rnd * (b - a +1)) + a)
Next

Print "unsort ";
For i = a To b : Print Using "####"; array(i); : Next : Print
gnomesort(array())  ' sort the array
Print "  sort ";
For i = a To b : Print Using "####"; array(i); : Next : Print

' empty keyboard buffer
While Inkey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End
Output:
unsort    4  -5   5   1  -3  -1  -2  -6   0   7  -4   6   2  -7   3
sort   -7  -6  -5  -4  -3  -2  -1   0   1   2   3   4   5   6   7

Gambas

Public Sub Main()
Dim siCount As Short
Dim siCounti As Short = 1
Dim siCountj As Short = 2
Dim siToSort As Short[] = [249, 28, 111, 36, 171, 98, 29, 448, 44, 147, 154, 46, 102, 183, 24]

Print "To sort: - ";
GoSub Display

While siCounti < siToSort.Count
If siToSort[siCounti - 1] <= siToSort[siCounti] Then
siCounti = siCountj
Inc siCountj
Else
Swap siToSort[siCounti - 1], siToSort[siCounti]
Dec siCounti
If siCounti = 0 Then
siCounti = siCountj
Inc siCountj
Endif
Endif
Wend

Print "Sorted: -  ";
GoSub Display

Return
'--------------------------------------------
Display:

For siCount = 0 To siToSort.Max
Print Format(Str(siToSort[siCount]), "####");
If siCount <> siToSort.max Then Print ",";
Next

Print
Return

End

Output:

To sort: -  249,  28, 111,  36, 171,  98,  29, 448,  44, 147, 154,  46, 102, 183,  24
Sorted: -    24,  28,  29,  36,  44,  46,  98, 102, 111, 147, 154, 171, 183, 249, 448

Go

package main

import "fmt"

func main() {
a := []int{170, 45, 75, -90, -802, 24, 2, 66}
fmt.Println("before:", a)
gnomeSort(a)
fmt.Println("after: ", a)
}

func gnomeSort(a []int) {
for i, j := 1, 2; i < len(a); {
if a[i-1] > a[i] {
a[i-1], a[i] = a[i], a[i-1]
i--
if i > 0 {
continue
}
}
i = j
j++
}
}

More generic version that sorts anything that implements sort.Interface:

package main

import (
"sort"
"fmt"
)

func main() {
a := []int{170, 45, 75, -90, -802, 24, 2, 66}
fmt.Println("before:", a)
gnomeSort(sort.IntSlice(a))
fmt.Println("after: ", a)
}

func gnomeSort(a sort.Interface) {
for i, j := 1, 2; i < a.Len(); {
if a.Less(i, i-1) {
a.Swap(i-1, i)
i--
if i > 0 {
continue
}
}
i = j
j++
}
}

Groovy

Solution:

def makeSwap = { a, i, j = i+1 -> print "."; a[[j,i]] = a[[i,j]] }

def checkSwap = { list, i, j = i+1 -> [(list[i] > list[j])].find{ it }.each { makeSwap(list, i, j) } }

def gnomeSort = { input ->
def swap = checkSwap.curry(input)
def index = 1
while (index < input.size()) {
index += (swap(index-1) && index > 1) ? -1 : 1
}
input
}

Test:

println (gnomeSort([23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4]))
println (gnomeSort([88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1]))

Output:

..............................................................................................................................................[4, 12, 14, 23, 24, 24, 31, 35, 38, 46, 51, 57, 57, 58, 76, 78, 89, 92, 95, 97, 99]
.........................................................................................................................................[0, 1, 4, 5, 7, 8, 12, 14, 18, 20, 31, 33, 44, 62, 70, 73, 75, 76, 78, 81, 82, 84, 88]

Haskell

gnomeSort [] = []
gnomeSort (x:xs) = gs [x] xs
where
gs vv@(v:vs) (w:ws)
| v<=w = gs (w:vv) ws
| otherwise = gs vs (w:v:ws)
gs [] (y:ys) = gs [y] ys
gs xs [] = reverse xs
-- keeping the first argument of gs in reverse order avoids the deterioration into cubic behaviour

Haxe

class GnomeSort {
@:generic
public static function sort<T>(arr:Array<T>) {
var i = 1;
var j = 2;
while (i < arr.length) {
if (Reflect.compare(arr[i - 1], arr[i]) <= 0) {
i = j++;
} else {
var temp = arr[i];
arr[i] = arr[i - 1];
arr[i - 1] = temp;
if (--i == 0) {
i = j++;
}
}
}
}
}

class Main {
static function main() {
var integerArray = [1, 10, 2, 5, -1, 5, -19, 4, 23, 0];
var floatArray = [1.0, -3.2, 5.2, 10.8, -5.7, 7.3,
3.5, 0.0, -4.1, -9.5];
var stringArray = ['We', 'hold', 'these', 'truths', 'to',
'be', 'self-evident', 'that', 'all',
'men', 'are', 'created', 'equal'];
Sys.println('Unsorted Integers: ' + integerArray);
GnomeSort.sort(integerArray);
Sys.println('Sorted Integers:   ' + integerArray);
Sys.println('Unsorted Floats:   ' + floatArray);
GnomeSort.sort(floatArray);
Sys.println('Sorted Floats:     ' + floatArray);
Sys.println('Unsorted Strings:  ' + stringArray);
GnomeSort.sort(stringArray);
Sys.println('Sorted Strings:    ' + stringArray);
}
}
Output:
Unsorted Integers: [1,10,2,5,-1,5,-19,4,23,0]
Sorted Integers:   [-19,-1,0,1,2,4,5,5,10,23]
Unsorted Floats:   [1,-3.2,5.2,10.8,-5.7,7.3,3.5,0,-4.1,-9.5]
Sorted Floats:     [-9.5,-5.7,-4.1,-3.2,0,1,3.5,5.2,7.3,10.8]
Unsorted Strings:  [We,hold,these,truths,to,be,self-evident,that,all,men,are,created,equal]
Sorted Strings:    [We,all,are,be,created,equal,hold,men,self-evident,that,these,to,truths]

Icon and Unicon

procedure main()                     #: demonstrate various ways to sort a list and string
demosort(gnomesort,[3, 14, 1, 5, 9, 2, 6, 3],"qwerty")
end

procedure gnomesort(X,op)            #: return sorted list
local i,j

op := sortop(op,X)                # select how and what we sort

j := (i := 2) + 1                 # translation of pseudo code
while i <= *X do {
if op(X[i],X[i-1]) then {
X[i] :=: X[i -:= 1]
if i > 1 then next
}
j := (i := j) + 1
}
return X
end

Note: This example relies on the supporting procedures 'sortop', and 'demosort' in Bubble Sort. The full demosort exercises the named sort of a list with op = "numeric", "string", ">>" (lexically gt, descending),">" (numerically gt, descending), a custom comparator, and also a string.

Abbreviated sample output:
Sorting Demo using procedure gnomesort
on list : [ 3 14 1 5 9 2 6 3 ]
with op = &null:         [ 1 2 3 3 5 6 9 14 ]   (0 ms)
...
on string : "qwerty"
with op = &null:         "eqrtwy"   (0 ms)

Io

Naive version:

List do(
gnomeSortInPlace := method(
idx := 1
while(idx <= size,
if(idx == 0 or at(idx) > at(idx - 1)) then(
idx = idx + 1
) else(
swapIndices(idx, idx - 1)
idx = idx - 1
)
)
self)
)

lst := list(5, -1, -4, 2, 9)
lst gnomeSortInPlace println # ==> list(-4, -1, 2, 5, 9)

Optimized version, storing the position before traversing back towards the begining of the list (Wikipedia)

List do(
gnomeSortInPlace := method(
idx1 := 1
idx2 := 2

while(idx1 <= size,
if(idx1 == 0 or at(idx1) > at(idx1 - 1)) then(
idx1 = idx2
idx2 = idx2 + 1
) else(
swapIndices(idx1, idx1 - 1)
idx1 = idx1 - 1
)
)
self)
)

lst := list(5, -1, -4, 2, 9)
lst gnomeSortInPlace println # ==> list(-4, -1, 2, 5, 9)

IS-BASIC

100 PROGRAM "GnomeSrt.bas"
110 RANDOMIZE
120 NUMERIC ARRAY(-5 TO 12)
130 CALL INIT(ARRAY)
140 CALL WRITE(ARRAY)
150 CALL GNOMESORT(ARRAY)
160 CALL WRITE(ARRAY)
170 DEF INIT(REF A)
180   FOR I=LBOUND(A) TO UBOUND(A)
190     LET A(I)=RND(98)+1
200   NEXT
210 END DEF
220 DEF WRITE(REF A)
230   FOR I=LBOUND(A) TO UBOUND(A)
240     PRINT A(I);
250   NEXT
260   PRINT
270 END DEF
280 DEF GNOMESORT(REF A)
290   LET I=LBOUND(A)+1:LET J=I+1
300   DO WHILE I<=UBOUND(A)
310     IF A(I-1)<=A(I) THEN
320       LET I=J:LET J=J+1
330     ELSE
340       LET T=A(I-1):LET A(I-1)=A(I):LET A(I)=T
350       LET I=I-1
360       IF I=LBOUND(A) THEN LET I=J:LET J=J+1
370     END IF
380   LOOP
390 END DEF

J

Generally, this task should be accomplished in J using /:~. Here we take an approach that's more comparable with the other examples on this page.
position=: 0 {.@I.@, [
swap=: ] A.~ *@position * #@[ !@- <:@position
gnome=: swap~ 2 >/\ ]
gnomes=: gnome^:_
Note 1: this implementation of swap is actually rather silly, and will not work on long lists. A better implementation would be:
swap=: position (] {~ _1 0 + [)`(0 _1 + [)`]}^:(*@[) ]
Note 2: this implementation only works for domains where > is defined (in J, "greater than" only works on numbers). To work around this issue, you could define:
gt=:  -.@(-: /:~)@,&<
gnome=: swap~ 2 gt/\ ]
Note 3: this implementation does not return intermediate results. If you want them, you could use
gnomeps=: gnome^:a:
Note 4: gnomeps just shows intermediate results and does not show the gnome's position. You can extract the gnome's position using an expression such as
2 ~:/\ gnomeps
.

Java

Translation of: C
public static void gnomeSort(int[] a)
{
int i=1;
int j=2;

while(i < a.length) {
if ( a[i-1] <= a[i] ) {
i = j; j++;
} else {
int tmp = a[i-1];
a[i-1] = a[i];
a[i--] = tmp;
i = (i==0) ? j++ : i;
}
}
}

JavaScript

function gnomeSort(a) {
function moveBack(i) {
for( ; i > 0 && a[i-1] > a[i]; i--) {
var t = a[i];
a[i] = a[i-1];
a[i-1] = t;
}
}
for (var i = 1; i < a.length; i++) {
if (a[i-1] > a[i]) moveBack(i);
}
return a;
}

jq

Works with: jq version 1.4

This implementation adheres to the specification. The array to be sorted, however, can be any JSON array.

# As soon as "condition" is true, then emit . and stop:
def do_until(condition; next):
def u: if condition then . else (next|u) end;
u;

# input: an array
def gnomeSort:
def swap(i;j): .[i] as \$x | .[i]=.[j] | .[j]=\$x;

length as \$length
# state: [i, j, ary]
| [1, 2, .]
| do_until( .[0] >= \$length;
.[0] as \$i | .[1] as \$j
| .[2]
# for descending sort, use >= for comparison
| if .[\$i-1] <= .[\$i] then [\$j, \$j + 1, .]
else swap( \$i-1; \$i)
| (\$i - 1) as \$i
| if \$i == 0 then [\$j, \$j + 1, .]
else [\$i, \$j, .]
end
end )
| .[2];

Example:

[(2|sqrt), [1], null, 1, 0.5, 2, 1, -3, {"a": "A"}] | gnomeSort
Output:
\$ jq -M -n -f Gnome_sort.jq
[
null,
-3,
0.5,
1,
1,
1.4142135623730951,
2,
[
1
],
{
"a": "A"
}
]

Julia

Works with: Julia version 0.6
function gnomesort!(arr::Vector)
i, j = 1, 2
while i < length(arr)
if arr[i]  arr[i+1]
i = j
j += 1
else
arr[i], arr[i+1] = arr[i+1], arr[i]
i -= 1
if i == 0
i = j
j += 1
end
end
end
return arr
end

v = rand(-10:10, 10)
println("# unordered: \$v\n -> ordered: ", gnomesort!(v))
Output:
# unordered: [9, -8, 0, 3, 2, 10, 5, 4, 5, 5]
-> ordered: [-8, 0, 2, 3, 4, 5, 5, 5, 9, 10]

Kotlin

// version 1.1.0

fun <T: Comparable<T>> gnomeSort(a: Array<T>, ascending: Boolean = true) {
var i = 1
var j = 2
while (i < a.size)
if (ascending && (a[i - 1] <= a[i]) ||
!ascending && (a[i - 1] >= a[i]))
i = j++
else {
val temp = a[i - 1]
a[i - 1] = a[i]
a[i--] = temp
if (i == 0) i = j++
}
}

fun main(args: Array<String>) {
val array = arrayOf(100, 2, 56, 200, -52, 3, 99, 33, 177, -199)
println("Original      : \${array.asList()}")
gnomeSort(array)
println("Sorted (asc)  : \${array.asList()}")
gnomeSort(array, false)
println("Sorted (desc) : \${array.asList()}")
}
Output:
Original      : [100, 2, 56, 200, -52, 3, 99, 33, 177, -199]
Sorted (asc)  : [-199, -52, 2, 3, 33, 56, 99, 100, 177, 200]
Sorted (desc) : [200, 177, 100, 99, 56, 33, 3, 2, -52, -199]

Lua

Keep in mind that Lua arrays initial index is 1.

function gnomeSort(a)
local i, j = 2, 3

while i <= #a do
if a[i-1] <= a[i] then
i = j
j = j + 1
else
a[i-1], a[i] = a[i], a[i-1] -- swap
i = i - 1
if i == 1 then -- 1 instead of 0
i = j
j = j + 1
end
end
end
end

Example:

list = { 5, 6, 1, 2, 9, 14, 2, 15, 6, 7, 8, 97 }
gnomeSort(list)
for i, j in pairs(list) do
print(j)
end

Maple

arr := Array([17,3,72,0,36,2,3,8,40,0]):
len := numelems(arr):
i := 2:
while (i <= len) do
if (i=1 or arr[i] >= arr[i-1]) then
i++:
else
temp:= arr[i]:
arr[i] := arr[i-1]:
arr[i-1] := temp:
i--:
end if:
end do:
arr;
Output:
[0,0,2,3,3,8,17,36,40,72]

Mathematica/Wolfram Language

gnomeSort[list_]:=Module[{i=2,j=3},
While[ i<=Length[[list]],
If[ list[[i-1]]<=list[[i]],
i=j; j++;,
list[[i-1;;i]]=list[[i;;i-1]];i--;];
If[i==1,i=j;j++;]
]]

MATLAB / Octave

function list = gnomeSort(list)

i = 2;
j = 3;

while i <= numel(list)

if list(i-1) <= list(i)
i = j;
j = j+1;
else
list([i-1 i]) = list([i i-1]); %Swap
i = i-1;
if i == 1
i = j;
j = j+1;
end
end %if

end %while
end %gnomeSort

Sample Usage:

>> gnomeSort([4 3 1 5 6 2])

ans =

1     2     3     4     5     6

MAXScript

fn gnomeSort arr =
(
local i = 2
local j = 3
while i <= arr.count do
(
if arr[i-1] <= arr[i] then
(
i = j
j += 1
)
else
(
swap arr[i-1] arr[i]
i -= 1
if i == 1 then
(
i = j
j += 1
)
)
)
return arr
)

Output:

a = for i in 1 to 10 collect random 1 20
#(20, 10, 16, 2, 19, 12, 11, 3, 5, 16)
gnomesort a
#(2, 3, 5, 10, 11, 12, 16, 16, 19, 20)

Metafont

def gnomesort(suffix v)(expr n) =
begingroup save i, j, t;
i := 1; j := 2;
forever: exitif not (i < n);
if v[i-1] <= v[i]:
i := j; j := j + 1;
else:
t := v[i-1];
v[i-1] := v[i];
v[i] := t;
i := i - 1;
i := if i=0: j; j := j + 1 else: i fi;
fi
endfor
endgroup enddef;
numeric a[];
for i = 0 upto 9: a[i] := uniformdeviate(40); message decimal a[i]; endfor
message char10;

gnomesort(a, 10);
for i = 0 upto 9: message decimal a[i]; endfor
end

NetRexx

/* NetRexx */
options replace format comments java crossref savelog symbols binary

import java.util.List

i1 = ArrayList(Arrays.asList([Integer(3), Integer(3), Integer(1), Integer(2), Integer(4), Integer(3), Integer(5), Integer(6)]))
say i1.toString
say gnomeSort(i1).toString

return

method isTrue public constant binary returns boolean
return 1 == 1

method isFalse public constant binary returns boolean
return \isTrue

method gnomeSort(a = String[], sAsc = isTrue) public constant binary returns String[]

rl = String[a.length]
al = List gnomeSort(Arrays.asList(a), sAsc)
al.toArray(rl)

return rl

method gnomeSort(a = List, sAsc = isTrue) public constant binary returns ArrayList

sDsc = \sAsc -- Ascending/descending switches
ra = ArrayList(a)
i_ = 1
j_ = 2
loop label i_ while i_ < ra.size
ctx = (Comparable ra.get(i_ - 1)).compareTo(Comparable ra.get(i_))
if (sAsc & ctx <= 0) | (sDsc & ctx >= 0) then do
i_ = j_
j_ = j_ + 1
end
else do
swap = ra.get(i_)
ra.set(i_, ra.get(i_ - 1))
ra.set(i_ - 1, swap)
i_ = i_ - 1
if i_ = 0 then do
i_ = j_
j_ = j_ + 1
end
end
end i_

return ra
Output
[3, 3, 1, 2, 4, 3, 5, 6]
[1, 2, 3, 3, 3, 4, 5, 6]

Nim

proc gnomeSort[T](a: var openarray[T]) =
var
n = a.len
i = 1
j = 2
while i < n:
if a[i-1] > a[i]:
swap a[i-1], a[i]
dec i
if i > 0: continue
i = j
inc j

var a = @[4, 65, 2, -31, 0, 99, 2, 83, 782]
gnomeSort a
echo a

Output:

@[-31, 0, 2, 2, 4, 65, 83, 99, 782]

Objeck

Translation of: C
function : GnomeSort(a : Int[]) {
i := 1;
j := 2;

while(i < a->Size()) {
if (a[i-1] <= a[i]) {
i := j;
j += 1;
}
else {
tmp := a[i-1];
a[i-1] := a[i];
a[i] := tmp;
i -= 1;
if(i = 0) {
i := j;
j += 1;
};
};
};
}

OCaml

from the toplevel:

# let gnome_sort a =
let i = ref 1
and j = ref 2 in
while !i < Array.length a do
if a.(!i-1) <= a.(!i) then
begin
i := !j;
j := !j + 1;
end else begin
swap a (!i-1) (!i);
i := !i - 1;
if !i = 0 then begin
i := !j;
j := !j + 1;
end;
end;
done;
;;
val gnome_sort : 'a array -> unit = <fun>

# let a = [| 7; 9; 4; 2; 1; 3; 6; 5; 0; 8; |] ;;
val a : int array = [|7; 9; 4; 2; 1; 3; 6; 5; 0; 8|]

# gnome_sort a ;;
- : unit = ()

# a ;;
- : int array = [|0; 1; 2; 3; 4; 5; 6; 7; 8; 9|]

Octave

function s = gnomesort(v)
i = 2; j = 3;
while ( i <= length(v) )
if ( v(i-1) <= v(i) )
i = j;
j++;
else
t = v(i-1);
v(i-1) = v(i);
v(i) = t;
i--;
if ( i == 1 )
i = j;
j++;
endif
endif
endwhile
s = v;
endfunction
v = [7, 9, 4, 2, 1, 3, 6, 5, 0, 8];
disp(gnomesort(v));

ooRexx

version 1

Translation of: NetRexx
/* Rexx */

call demo
return
exit

-- -----------------------------------------------------------------------------
--  Gnome sort implementation
-- -----------------------------------------------------------------------------
::routine gnomeSort
use arg ra, sAsc = ''
if sAsc = '' then sAsc = isTrue()

sDsc = \sAsc -- Ascending/descending switches
i_ = 1
j_ = 2
loop label i_ while i_ < ra~items()
ctx = (ra~get(i_ - 1))~compareTo(ra~get(i_))
if (sAsc & ctx <= 0) | (sDsc & ctx >= 0) then do
i_ = j_
j_ = j_ + 1
end
else do
swap = ra~get(i_)
ra~set(i_, ra~get(i_ - 1))
ra~set(i_ - 1, swap)
i_ = i_ - 1
if i_ = 0 then do
i_ = j_
j_ = j_ + 1
end
end
end i_

return ra

-- -----------------------------------------------------------------------------
-- Demonstrate the implementation
-- -----------------------------------------------------------------------------
::routine demo
placesList = .nlist~of( -
"UK  London",     "US  New York",   "US  Boston",     "US  Washington" -
, "UK  Washington", "US  Birmingham", "UK  Birmingham", "UK  Boston"     -
)

lists = .nlist~of( -
placesList -
, gnomeSort(placesList~copy()) -
)

loop ln = 0 to lists~items() - 1
cl = lists[ln]
loop ct = 0 to cl~items() - 1
say right(ct + 1, 3)':' cl[ct]
end ct
say
end ln

i_.0 = 3
i_.1 = .nlist~of(3, 3, 1, 2, 4, 3, 5, 6)
i_.2 = gnomeSort(i_.1~copy(), isTrue())
i_.3 = gnomeSort(i_.1~copy(), isFalse())
loop s_ = 1 to i_.0
ss = ''
loop x_ = 0 to i_.s_~items() - 1
ss ||= right(i_.s_~get(x_), 3)' '
end x_
say strip(ss, 'T')
end s_

return

-- -----------------------------------------------------------------------------
::routine isTrue
return 1 == 1

-- -----------------------------------------------------------------------------
::routine isFalse
return \isTrue()

-- -----------------------------------------------------------------------------
-- Helper class.  Map get and set methods for easier conversion from java.util.List
-- -----------------------------------------------------------------------------
::class NList mixinclass List public

-- Map get() to at()
::method get
use arg ix
return self~at(ix)

-- Map set() to put()
::method set
use arg ix, item
self~put(item, ix)
return

Output:

1: UK  London
2: US  New York
3: US  Boston
4: US  Washington
5: UK  Washington
6: US  Birmingham
7: UK  Birmingham
8: UK  Boston

1: UK  Birmingham
2: UK  Boston
3: UK  London
4: UK  Washington
5: US  Birmingham
6: US  Boston
7: US  New York
8: US  Washington

3   3   1   2   4   3   5   6
1   2   3   3   3   4   5   6
6   5   4   3   3   3   2   1

version 2

Translation of: REXX
/* REXX ---------------------------------------------------------------
* 28.06.2014 Walter Pachl
* 30.06.2014 corrected in sync with REXX version 2
*--------------------------------------------------------------------*/
Call gen                         /* generate the array elements.   */
Call show 'before sort'          /* show  "before"  array elements.*/
Call gnomeSort x                 /* invoke the infamous gnome sort.*/
Call show ' after sort'          /* show  "after"   array elements.*/
Exit                             /* done.                          */

gnomesort: Procedure
Use Arg x
n=x~items
k=2
Do j=3 While k<=n
km=k-1
If x[km]<=x[k] Then
k=j
Else Do
t=x[km]; x[km]=x[k]; x[k]=t  /* swap two entries in the array. */
k=k-1
If k==1 Then
k=j
Else
j=j-1
End
End
Return

gen:
x=.array~of('---the seven virtues---','=======================',,
'Faith','Hope','Charity  [Love]','Fortitude','  Justice',,
'Prudence','Temperance')
Return
show:
Say arg(1)
Do i=1 To x~items
Say 'element' right(i,2) x[i]
End
Return

output Similar to REXX version 2

Oz

Translation of: Haskell
declare
fun {GnomeSort Xs}
case Xs of nil then nil
[] X|Xr then {Loop [X] Xr}
end
end

fun {Loop Vs Ws}
case [Vs Ws]
of [V|_  W|Wr] andthen V =< W then {Loop W|Vs Wr}
[] [V|Vr W|Wr] then {Loop Vr W|V|Wr}
[] [nil  W|Wr] then {Loop [W] Wr}
[] [Vs   nil ] then {Reverse Vs}
end
end
in
{Show {GnomeSort [3 1 4 1 5 9 2 6 5]}}

PARI/GP

gnomeSort(v)={
my(i=2,j=3,n=#v,t);
while(i<=n,
if(v[i-1]>v[i],
t=v[i];
v[i]=v[i-1];
v[i--]=t;
if(i==1, i=j; j++);
,
i=j;
j++
)
);
v
};

Pascal

procedure gnomesort(var arr : Array of Integer; size : Integer);
var
i, j, t	: Integer;
begin
i := 1;
j := 2;
while i < size do begin
if arr[i-1] <= arr[i] then
begin
i := j;
j := j + 1
end
else begin
t := arr[i-1];
arr[i-1] := arr[i];
arr[i] := t;
i := i - 1;
if i = 0 then begin
i := j;
j := j + 1
end
end
end;
end;

Perl

use strict;

sub gnome_sort
{
my @a = @_;

my \$size = scalar(@a);
my \$i = 1;
my \$j = 2;
while(\$i < \$size) {
if ( \$a[\$i-1] <= \$a[\$i] ) {
\$i = \$j;
\$j++;
} else {
@a[\$i, \$i-1] = @a[\$i-1, \$i];
\$i--;
if (\$i == 0) {
\$i = \$j;
\$j++;
}
}
}
return @a;
}
my @arr = ( 10, 9, 8, 5, 2, 1, 1, 0, 50, -2 );
print "\$_\n" foreach gnome_sort( @arr );

Phix

with javascript_semantics

function gnomeSort(sequence s)
integer i = 1, j = 2
while i<length(s) do
object si = s[i],
sn = s[i+1]
if si<=sn then
i = j
j += 1
else
s[i] = sn
s[i+1] = si
i -= 1
if i = 0 then
i = j
j += 1
end if
end if
end while
return s
end function

?gnomeSort(shuffle(tagset(10)))

PHP

function gnomeSort(\$arr){
\$i = 1;
\$j = 2;
while(\$i < count(\$arr)){
if (\$arr[\$i-1] <= \$arr[\$i]){
\$i = \$j;
\$j++;
}else{
list(\$arr[\$i],\$arr[\$i-1]) = array(\$arr[\$i-1],\$arr[\$i]);
\$i--;
if(\$i == 0){
\$i = \$j;
\$j++;
}
}
}
return \$arr;
}
\$arr = array(3,1,6,2,9,4,7,8,5);
echo implode(',',gnomeSort(\$arr));
1,2,3,4,5,6,7,8,9

PicoLisp

(de gnomeSort (Lst)
(let J (cdr Lst)
(for (I Lst (cdr I))
(if (>= (cadr I) (car I))
(setq I J  J (cdr J))
(xchg I (cdr I))
(if (== I Lst)
(setq I J  J (cdr J))
(setq I (prior I Lst)) ) ) ) )
Lst )

PL/I

SORT: PROCEDURE OPTIONS (MAIN);
DECLARE A(0:9) FIXED STATIC INITIAL (5, 2, 7, 1, 9, 8, 6, 3, 4, 0);

CALL GNOME_SORT (A);
put skip edit (A) (f(7));

GNOME_SORT: PROCEDURE (A) OPTIONS (REORDER); /* 9 September 2015 */
declare A(*) fixed;
declare t fixed;
declare (i, j) fixed;

i = 1; j = 2;
do while (i <= hbound(A));
if a(i-1) <= a(i) then
do;
i = j; j = j + 1;
end;
else
do;
t = a(i-1); a(i-1) = a(i); a(i) = t;
i = i - 1;
if i = 0 then do; i = j; j = j + 1; end;
end;
end;

END GNOME_SORT;

END SORT;

Results:

0      1      2      3      4      5      6      7      8      9

PowerBASIC

The BASIC example will work as-is if the array is declared in the same function as the sort. This example doesn't require that, but forces you to know your data type beforehand.

SUB gnomeSort (a() AS LONG)
DIM i AS LONG, j AS LONG
i = 1
j = 2
WHILE (i < UBOUND(a) + 1)
IF (a(i - 1) <= a(i)) THEN
i = j
INCR j
ELSE
SWAP a(i - 1), a(i)
DECR i
IF 0 = i THEN
i = j
INCR j
END IF
END IF
WEND
END SUB

FUNCTION PBMAIN () AS LONG
DIM n(9) AS LONG, x AS LONG
RANDOMIZE TIMER
OPEN "output.txt" FOR OUTPUT AS 1
FOR x = 0 TO 9
n(x) = INT(RND * 9999)
PRINT #1, n(x); ",";
NEXT
PRINT #1,
gnomeSort n()
FOR x = 0 TO 9
PRINT #1, n(x); ",";
NEXT
CLOSE 1
END FUNCTION

Sample output:

7426 , 7887 , 8297 , 2671 , 7586 , 7160 , 1195 , 665 , 9352 , 6199 ,
665 , 1195 , 2671 , 6199 , 7160 , 7426 , 7586 , 7887 , 8297 , 9352 ,

PowerShell

function gnomesort(\$a) {
\$size, \$i, \$j = \$a.Count, 1, 2
while(\$i -lt \$size) {
if (\$a[\$i-1] -le \$a[\$i]) {
\$i = \$j
\$j++
}
else {
\$a[\$i-1], \$a[\$i] = \$a[\$i], \$a[\$i-1]
\$i--
if(\$i -eq 0) {
\$i = \$j
\$j++
}
}
}
\$a
}
\$array = @(60, 21, 19, 36, 63, 8, 100, 80, 3, 87, 11)
"\$(gnomesort \$array)"

Output:

3 8 11 19 21 36 60 63 80 87 100

PureBasic

Procedure GnomeSort(Array a(1))
Protected Size = ArraySize(a()) + 1
Protected i = 1, j = 2

While i < Size
If a(i - 1) <= a(i)
;for descending SORT, use >= for comparison
i = j
j + 1
Else
Swap a(i - 1), a(i)
i - 1
If i = 0
i = j
j + 1
EndIf
EndIf
Wend
EndProcedure

Python

>>> def gnomesort(a):
i,j,size = 1,2,len(a)
while i < size:
if a[i-1] <= a[i]:
i,j = j, j+1
else:
a[i-1],a[i] = a[i],a[i-1]
i -= 1
if i == 0:
i,j = j, j+1
return a

>>> gnomesort([3,4,2,5,1,6])
[1, 2, 3, 4, 5, 6]
>>>

Quackery

[ dup size times
[ i^ 0 > if
[ dup i^ 1 - peek
over i^ peek
2dup > iff
[ dip [ swap i^ poke ]
swap i^ 1 - poke
-1 step ]
else 2drop ] ] ]         is gnomesort ( [ --> [ )

R

Starting from 1

gnomesort <- function(x)
{
i <- 1
j <- 1
while(i < length(x))
{
if(x[i] <= x[i+1])
{
i <- j
j <- j+1
} else
{
temp <- x[i]
x[i] <- x[i+1]
x[i+1]  <- temp
i <- i - 1
if(i == 0)
{
i <- j
j <- j+1
}
}
}
x
}
gnomesort(c(4, 65, 2, -31, 0, 99, 83, 782, 1)) # -31   0   1   2   4  65  83  99 782

Starting from 2

The previously solution misses out on a cool R trick for swapping items.

As R is 1-indexed, we need to make some minor adjustments to the given pseudo-code. To give some variety and to remove the previous solution's potentially redundant first run, we have chosen a different adjustment to the previous solution's. We have otherwise aimed to be faithful to the pseudo-code.

gnomeSort <- function(a)
{
i <- 2
j <- 3
while(i <= length(a))
{
if(a[i - 1] <= a[i])
{
i <- j
j <- j + 1
}
else
{
a[c(i - 1, i)] <- a[c(i, i - 1)]#The cool trick mentioned above.
i <- i - 1
if(i == 1)
{
i <- j
j <- j + 1
}
}
}
a
}
#Examples taken from the Haxe solution.
#Note that R can use <= to compare strings.
ints <- c(1, 10, 2, 5, -1, 5, -19, 4, 23, 0)
numerics <- c(1, -3.2, 5.2, 10.8, -5.7, 7.3, 3.5, 0, -4.1, -9.5)
strings <- c("We", "hold", "these", "truths", "to", "be", "self-evident", "that", "all", "men", "are", "created", "equal")
Output:
> gnomeSort(ints)
[1] -19  -1   0   1   2   4   5   5  10  23
> gnomeSort(numerics)
[1] -9.5 -5.7 -4.1 -3.2  0.0  1.0  3.5  5.2  7.3 10.8
> gnomeSort(strings)
[1] "all"          "are"          "be"           "created"      "equal"        "hold"         "men"
[8] "self-evident" "that"         "these"        "to"           "truths"       "We"

Racket

#lang racket

;; Translation of the pseudo code
(define (gnome-sort1 a <=?)
(define size (vector-length a))
(define (swap i j)
(define t (vector-ref a i))
(vector-set! a i (vector-ref a j))
(vector-set! a j t))
(let loop ([i 1] [j 2])
(when (< i size)
(if (<=? (vector-ref a (sub1 i)) (vector-ref a i))
(loop j (add1 j))
(begin (swap (sub1 i) i)
(let ([i (sub1 i)])
(if (zero? i)
(loop j (add1 j))
(loop i j)))))))
a)
(gnome-sort1 (vector 3 2 1 4 5 6) <=)

;; a functional version, roughly like the Scheme entry
(define (gnome-sort2 l <=?)
(match l
[(list) l]
[(list x xs ...)
(let loop ([x `((,x) . ,xs)])
(match x
[`(,ps) ps]
[`((,p . ,ps) ,n . ,ns)
(loop (cond [(<=? n p)  `((,n ,p . ,ps) . ,ns)]
[(null? ps) `((,n) ,p . ,ns)]
[else       `(,ps ,n ,p . ,ns)]))]))]))
(gnome-sort2 '(3 2 1 4 5 6) <=)

Raku

(formerly Perl 6)

Works with: rakudo version 2016.03
sub gnome_sort (@a) {
my (\$i, \$j) = 1, 2;
while \$i < @a {
if @a[\$i - 1] <= @a[\$i] {
(\$i, \$j) = \$j, \$j + 1;
}
else {
(@a[\$i - 1], @a[\$i]) = @a[\$i], @a[\$i - 1];
\$i--;
(\$i, \$j) = \$j, \$j + 1 if \$i == 0;
}
}
}

my @n = (1..10).roll(20);
say @n.&gnome_sort ~~ @n.sort ?? 'ok' !! 'not ok';

Rascal

import List;

public list[int] gnomeSort(a){
i = 1;
j = 2;
while(i < size(a)){
if(a[i-1] <= a[i]){
i = j;
j += 1;}
else{
temp = a[i-1];
a[i-1] = a[i];
a[i] = temp;
i = i - 1;
if(i == 0){
i = j;
j += 1;}}}
return a;
}

An example output:

gnomeSort([4, 65, 2, -31, 0, 99, 83, 782, 1])
list[int]: [-31,0,1,2,4,65,83,99,782]

REXX

version 1

This REXX version uses an unity-based array   (instead of a zero-based array).

/*REXX program sorts an array using the gnome sort algorithm (elements contain blanks). */
call gen                                         /*generate the  @   stemmed array.     */
call show     'before sort'                      /*display the   before  array elements.*/
say copies('▒', 60) /*show a separator line between sorts. */
call gnomeSort  #                                /*invoke the well─known  gnome  sort.  */
call show     ' after sort'                      /*display the    after  array elements.*/
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
gen: @.=;  @.1= '---the seven virtues---';    @.4= "Hope"           ;    @.7= 'Justice'
@.2= '=======================';    @.5= "Charity  [Love]";    @.8= 'Prudence'
@.3= 'Faith'                  ;    @.6= "Fortitude"      ;    @.9= 'Temperance'
do #=1  while @.#\==''; end;   #= #-1;   w= length(#);  return /*get #items*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
gnomeSort: procedure expose @.;  parse arg n;     k= 2            /*N: is number items. */
do j=3  while k<=n;                  p= k - 1        /*P: is previous item.*/
if @.p<<=@.k  then do;      k= j;    iterate;   end  /*order is OK so far. */
_= @.p;       @.p= @.k;     @.k= _                   /*swap two @ entries. */
k= k - 1;     if k==1  then k= j;    else j= j-1     /*test for 1st index. */
end    /*j*/;                                return
/*──────────────────────────────────────────────────────────────────────────────────────*/
show:  do j=1  for #;   say '       element'  right(j, w)  arg(1)":"  @.j;   end;   return
output:

(Shown at three-quarter size.)

element 1 before sort: ---the seven virtues---
element 2 before sort: =======================
element 3 before sort: Faith
element 4 before sort: Hope
element 5 before sort: Charity  [Love]
element 6 before sort: Fortitude
element 7 before sort: Justice
element 8 before sort: Prudence
element 9 before sort: Temperance
▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒
element 1  after sort: ---the seven virtues---
element 2  after sort: =======================
element 3  after sort: Charity  [Love]
element 4  after sort: Faith
element 5  after sort: Fortitude
element 6  after sort: Hope
element 7  after sort: Justice
element 8  after sort: Prudence
element 9  after sort: Temperance

version 2

/* REXX ---------------------------------------------------------------
* 28.06.2014 Walter Pachl  cf ooRexx version 2
* only style changes (reformatting) and adapt for ooRexx compatibility
* NOTE that leading blanks are ignored in the comparison ('  Justice')
* unless strict comparison is used  (i.e., 'If x.km<<=x.k Then')
* 30.06.2014 WP added the missing else clause
*--------------------------------------------------------------------*/
/* generate the array elements.   */
Call gen '---the seven virtues---','=======================',,
'Faith','Hope','Charity  [Love]','Fortitude','  Justice',,
'Prudence','Temperance'
Call show 'before sort'          /* show  "before"  array elements.*/
Call gnomeSort                   /* invoke the infamous gnome sort.*/
Call show ' after sort'          /* show  "after"   array elements.*/
Exit                             /* done.                          */

gnomesort: Procedure Expose x.
k=2
Do j=3 While k<=x.0
km=k-1
If x.km<=x.k Then
k=j
Else Do
t=x.km; x.km=x.k; x.k=t      /* swap two entries in the array. */
k=k-1
If k==1 Then
k=j
Else
j=j-1
End
End
Return

gen: Procedure Expose x.
Do i=1 To arg()
x.i=arg(i)
End
x.0=arg()
Return

show:  Procedure Expose x.
Say arg(1)
Do i=1 To x.0
Say 'element' right(i,2) x.i
End
Return

output

before sort
element  1 ---the seven virtues---
element  2 =======================
element  3 Faith
element  4 Hope
element  5 Charity  [Love]
element  6 Fortitude
element  7   Justice
element  8 Prudence
element  9 Temperance
after sort
element  1 ---the seven virtues---
element  2 =======================
element  3 Charity  [Love]
element  4 Faith
element  5 Fortitude
element  6 Hope
element  7   Justice
element  8 Prudence
element  9 Temperance

Ring

aList = [ 5, 6, 1, 2, 9, 14, 15, 7, 8, 97]
gnomeSort(aList)
for i=1 to len(aList)
see "" + aList[i] + " "
next

func gnomeSort a
i = 2
j = 3
while i < len(a)
if a[i-1] <= a[i]
i = j
j = j + 1
else
temp = a[i-1]
a[i-1] = a[i]
a[i] = temp
i = i - 1
if i = 1
i = j
j = j + 1 ok ok end

Ruby

class Array
def gnomesort!
i, j = 1, 2
while i < length
if self[i-1] <= self[i]
i, j = j, j+1
else
self[i-1], self[i] = self[i], self[i-1]
i -= 1
if i == 0
i, j = j, j+1
end
end
end
self
end
end
ary = [7,6,5,9,8,4,3,1,2,0]
ary.gnomesort!
# => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

Rust

fn gnome_sort<T: PartialOrd>(a: &mut [T]) {
let len = a.len();
let mut i: usize = 1;
let mut j: usize = 2;
while i < len {
if a[i - 1] <= a[i] {
// for descending sort, use >= for comparison
i = j;
j += 1;
} else {
a.swap(i - 1, i);
i -= 1;
if i == 0 {
i = j;
j += 1;
}
}
}
}

fn main() {
let mut v = vec![10, 8, 4, 3, 1, 9, 0, 2, 7, 5, 6];
println!("before: {:?}", v);
gnome_sort(&mut v);
println!("after:  {:?}", v);
}
Output:
before: [10, 8, 4, 3, 1, 9, 0, 2, 7, 5, 6]
after:  [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Scala

object GnomeSort {
def gnomeSort(a: Array[Int]): Unit = {
var (i, j) = (1, 2)
while ( i < a.length)
if (a(i - 1) <= a(i)) { i = j; j += 1 }
else {
val tmp = a(i - 1)
a(i - 1) = a(i)
a({i -= 1; i + 1}) = tmp
i = if (i == 0) {j += 1; j - 1} else i
}
}
}

Scheme

; supply comparison function, which returns true if first and second
; arguments are in order or equal.
(define (gnome-sort-compar in-order input-list)
(let gnome ((p (list (car input-list)))
(n (cdr input-list)))
(if (null? n) ; no more flowerpots?
p ; we're done
(let ((prev-pot (car p))
(next-pot (car n)))
(if (in-order next-pot prev-pot)
; if the pots are in order, step forwards.
; otherwise, exchange the two pots, and step backwards.
(gnome (cons next-pot p) ; Prev list grows
(cdr n)) ; Next list shorter by one
(if (null? (cdr p)) ; are we at the beginning?
(gnome                    ; if so, we can't step back
(list next-pot)          ; simply exchange the pots without
(cons prev-pot (cdr n))) ; changing lengths of lists
(gnome
(cdr p) ; Prev list shorter by one
(cons next-pot (cons prev-pot (cdr n))))))))))
#;1> (gnome-sort-compar <= '(98 36 2 78 5 81 32 90 73 21 94 28 53 25 10 99))
(2 5 10 21 25 28 32 36 53 73 78 81 90 94 98 99)

Sidef

class Array {
method gnomesort {
var (i=1, j=2);
var len = self.len;
while (i < len) {
if (self[i-1] <= self[i]) {
(i, j) = (j, j+1);
}
else {
self[i-1, i] = self[i, i-1];
if (--i == 0) {
(i, j) = (j, j+1);
}
}
}
return self;
}
}

var ary = [7,6,5,9,8,4,3,1,2,0];
say ary.gnomesort;
Output:
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

Smalltalk

Smalltalk at: #gnomesort put: nil.

"Utility"
OrderedCollection extend [
swap: a with: b [ |t|
t := self at: a.
self at: a put: b.
self at: b put: t
]
].

"Gnome sort as block closure"
gnomesort := [ :c |
|i j|
i := 2. j := 3.
[ i <= (c size) ]
whileTrue: [
(c at: (i-1)) <= (c at: i)
ifTrue: [
i := j copy.
j := j + 1.
]
ifFalse: [
c swap: (i-1) with: i.
i := i - 1.
i == 1
ifTrue: [
i := j copy.
j := j + 1
]
]
]
].

Testing

|r o|
r := Random new.
o := OrderedCollection new.

1 to: 10 do: [ :i | o add: (r between: 0 and: 50) ].

gnomesort value: o.

1 to: 10 do: [ :i | (o at: i) displayNl ].

SNOBOL4

Implementation of the Gnome sort. Note this is an overengineered approach that performs many checks the real world would need but might obfuscate intent. As such the actual implementation is carefully labelled and the rest can be ignored except as interest dictates.

*** GNOME SORT *****************************************************************
* GNOME(V)    -- gnome sort of the numerical vector V.
*** HELPER FUNCTIONS ***********************************************************
* IDXMAX(V)   -- highest index of vector V.
* IDXMIN(V)   -- lowest index of vector V.
* NUMBER(V)   -- succeeds if V is some form of numerical data, fails otherwise.
* NUMBERS(V)  -- succeeds iff all elements of vector V are numerical
* SWAP(A,B)   -- swaps the values of two variables (named with .var).
* VECTOR(V)   -- succeeds iff V is a vector.
********************************************************************************
define('GNOME(V)I,J,K,L,H,T')
*
define('IDXMAX(V)')
define('IDXMIN(V)')
define('NUMBER(V)')
define('NUMBERS(V)I,M')
define('SWAP(SWAP_PARAMETER_VAR_A,SWAP_PARAMETER_VAR_B)')
define('VECTOR(V)')
:(GNOME.END)

****************************************
* GNOME FUNCTION                       *
****************************************
GNOME         numbers(v)                                  :F(FRETURN)
gnome = copy(v)
l = idxmin(v) ; h = idxmax(v) ; i = l + 1
GNOME.LOOP    j = i - 1
le(i, l)                                    :S(GNOME.FORWARD)
gt(i,h)                                     :S(RETURN)
le(gnome<j>, gnome<i>)                      :S(GNOME.FORWARD)
swap(.gnome<j>, .gnome<i>)
i = i - 1                                   :(GNOME.LOOP)
GNOME.FORWARD i = i + 1                                   :(GNOME.LOOP)

****************************************
* HELPER FUNCTIONS                     *
****************************************
IDXMAX        vector(v)                                   :F(FRETURN)
prototype(v) ':' span('-' &digits) . idxmax :S(RETURN)F(IDXMAX.NORM)
IDXMAX.NORM   idxmax = prototype(v)                       :(RETURN)
****************************************
IDXMIN        vector(v)                                   :F(FRETURN)
prototype(v) span('-' &digits) . idxmin ':' :S(RETURN)F(IDXMIN.NORM)
IDXMIN.NORM   idxmin = 1                                  :(RETURN)
****************************************
NUMBER      ident(datatype(v), 'INTEGER')                 :S(RETURN)
ident(datatype(v), 'REAL')                    :S(RETURN)F(FRETURN)
****************************************
NUMBERS       vector(v)                                   :F(FRETURN)
i = idxmin(v) ; m = idxmax(v)
NUMBERS.LOOP  le(i,m)                                     :F(RETURN)
number(v<i>)                                :F(FRETURN)
i = i + 1                                   :(NUMBERS.LOOP)
****************************************
SWAP        SWAP = \$SWAP_PARAMETER_VAR_A
\$SWAP_PARAMETER_VAR_A = \$SWAP_PARAMETER_VAR_B
\$SWAP_PARAMETER_VAR_B = SWAP
SWAP =                                        :(RETURN)
****************************************
VECTOR        ident(v)                                    :S(FRETURN)
prototype(v) ','                            :S(FRETURN)F(RETURN)
****************************************
GNOME.END

The test script looks like this:

-INCLUDE 'gnome_sort.sno'

GNOME.TEST  output = 'valid values...'
a = array(5)
a<1> = 50 ; a<2> = 40 ; a<3> = 10
a<4> = 30 ; a<5> = 20
b = gnome(a)                                :F(ERROR)
eq(b<1>,10) ; eq(b<2>,20) ; eq(b<3>,30)     :F(ERROR)
eq(b<4>,40) ; eq(b<5>,50)                   :F(ERROR)
a = array('-2:2')
a<-2> = 50 ; a<-1> = 40 ; a<0> = 10
a<1> = 30 ; a<2> = 20
b = gnome(a)                                :F(ERROR)
eq(b<-2>,10) ; eq(b<-1>,20) ; eq(b<0>,30)   :F(ERROR)
eq(b<1>,40) ; eq(b<2>,50)                   :F(ERROR)
a = array(5)
a<1> = 5.5 ; a<2> = 4.4 ; a<3> = 1.1
a<4> = 3.3 ; a<5> = 2.2
b = gnome(a)                                :F(ERROR)
eq(b<1>,1.1) ; eq(b<2>,2.2) ; eq(b<3>,3.3)  :F(ERROR)
eq(b<4>,4.4) ; eq(b<5>,5.5)                 :F(ERROR)
output = 'invalid values...'
a = array(5, "five")
b = gnome(a)                                :S(ERROR)
a = array(5)
b = gnome(a)                                :S(ERROR)
output = 'PASSED!'

END

Swift

func gnomeSort<T: Comparable>(_ a: inout [T]) {
var i = 1
var j = 2
while i < a.count {
if a[i - 1] <= a[i] {
i = j
j += 1
} else {
a.swapAt(i - 1, i)
i -= 1
if i == 0 {
i = j
j += 1
}
}
}
}

var array = [10, 8, 4, 3, 1, 9, 0, 2, 7, 5, 6]
print("before: \(array)")
gnomeSort(&array)
print(" after: \(array)")
Output:
before: [10, 8, 4, 3, 1, 9, 0, 2, 7, 5, 6]
after: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Tcl

Library: Tcllib (Package: struct::list)
package require Tcl 8.5
package require struct::list

proc gnomesort {a} {
set i 1
set j 2
set size [llength \$a]
while {\$i < \$size} {
if {[lindex \$a [expr {\$i - 1}]] <= [lindex \$a \$i]} {
set i \$j
incr j
} else {
struct::list swap a [expr {\$i - 1}] \$i
incr i -1
if {\$i == 0} {
set i \$j
incr j
}
}
}
return \$a
}

puts [gnomesort {8 6 4 2 1 3 5 7 9}] ;# => 1 2 3 4 5 6 7 8 9

TI-83 BASIC

Store input into L1, run prgmSORTGNOM, output will be in L2.

:1→P
:L1→L2
:While P<dim(L2)
:If PP=1
:Then
:P+1→P
:Else
:If L2(P)≥L2(P-1)
:Then
:P+1→P
:Else
:L2(P)→Q
:L2(P-1)→L2(P)
:Q→L2(P-1)
:P-1→P
:End
:End
:End
:If L2(dim(L2))<L2(dim(L2)-1)
:Then
:L2(dim(L2))→Q
:L2(dim(L2)-1)→L2(dim(L2))
:Q→L2(dim(L2)-1)
:End
:DelVar P
:DelVar Q
:Return

True BASIC

Translation of: IS-BASIC
RANDOMIZE                         !RAMDOMZE TIMER en QBASIC
DIM array(-5 TO 12)
CALL iniciarray(array())
PRINT "unsort: ";
CALL escritura(array())
CALL gnomeSort(array())
PRINT
PRINT "  sort: ";
CALL escritura(array())
END

SUB escritura (array())
FOR i = LBOUND(array) TO UBOUND(array)
PRINT array(i);
NEXT i
PRINT
END SUB

SUB gnomeSort (array())
LET i = LBOUND(array) + 1
LET j = i + 1
DO WHILE i <= UBOUND(array)
IF array(i - 1) <= array(i) THEN
LET i = j
LET j = j + 1
ELSE
LET T = array(i - 1)
LET array(i - 1) = array(i)
LET array(i) = T
LET i = i - 1
IF i = LBOUND(array) THEN
LET i = j
LET j = j + 1
END IF
END IF
LOOP
END SUB

SUB iniciarray (array())
FOR i = LBOUND(array) TO UBOUND(array)
LET array(i) = (RND * 98) + 1
NEXT i
END SUB

uBasic/4tH

PRINT "Gnome sort:"
n = FUNC (_InitArray)
PROC _ShowArray (n)
PROC _Gnomesort (n)
PROC _ShowArray (n)
PRINT

END

_Gnomesort PARAM (1)                   ' Gnome sort
LOCAL (2)
b@=1
c@=2

DO WHILE b@ < a@
IF @(b@-1) > @(b@) THEN
PROC _Swap (b@, b@-1)
b@ = b@ - 1
IF b@ THEN
CONTINUE
ENDIF
ENDIF
b@ = c@
c@ = c@ + 1
LOOP
RETURN

_Swap PARAM(2)                         ' Swap two array elements
PUSH @(a@)
@(a@) = @(b@)
@(b@) = POP()
RETURN

_InitArray                             ' Init example array
PUSH 4, 65, 2, -31, 0, 99, 2, 83, 782, 1

FOR i = 0 TO 9
@(i) = POP()
NEXT

RETURN (i)

_ShowArray PARAM (1)                   ' Show array subroutine
FOR i = 0 TO a@-1
PRINT @(i),
NEXT

PRINT
RETURN

Ursala

The function is parameterized by a relational predicate and operates on a list. The algorithm is to scan forward until finding an item out of order, bubble it backwards to its proper position and resume scanning forward from where it was.

gnome_sort "p" =

@NiX ^=lx -+                                                                     # iteration
~&r?\~& @lNXrX ->llx2rhPlrPCTxPrtPX~&lltPlhPrCXPrX ~&ll&& @llPrXh not "p",    # backward bubble
->~&rhPlCrtPX ~&r&& ~&lZ!| @bh "p"+-                                          # forward scan

Most of the code is wasted on dull but unavoidable stack manipulations. Here is a test program using the lexical partial order relation.

#import std
#cast %s

t = gnome_sort(lleq) 'dfijhkwlawfkjnksdjnoqwjefgflkdsgioi'

output:

'adddeffffgghiiijjjjkkkkllnnooqsswww'

VBA

Translation of: Phix
Private Function gnomeSort(s As Variant) As Variant
Dim i As Integer: i = 1
Dim j As Integer: j = 2
Dim tmp As Integer
Do While i < UBound(s)
If s(i) <= s(i + 1) Then
i = j
j = j + 1
Else
tmp = s(i)
s(i) = s(i + 1)
s(i + 1) = tmp
i = i - 1
If i = 0 Then
i = j
j = j + 1
End If
End If
Loop
gnomeSort = s
End Function

Public Sub main()
Debug.Print Join(gnomeSort([{5, 3, 1, 7, 4, 1, 1, 20}]), ", ")
End Sub
Output:
1, 1, 1, 3, 4, 5, 7, 20

VBScript

Implementation

function gnomeSort( a )
dim i
dim j
i = 1
j = 2
do while i < ubound( a ) + 1
if a(i-1) <= a(i) then
i = j
j = j + 1
else
swap a(i-1), a(i)
i = i - 1
if i = 0 then
i = j
j = j + 1
end if
end if
loop
gnomeSort = a
end function

sub swap( byref x, byref y )
dim temp
temp = x
x = y
y = temp
end sub

Invocation

dim a
dim b

a = array( "zanzibar", "aardvark","ampicillin","zulu","gogodala", "wolverhampton")
b = gnomeSort( a )
wscript.echo join(a, ", ")

a = array( 234,567,345,568,2345,89,547,23,649,5769,456,456,567)
b = gnomeSort( a )
wscript.echo join(a, ", ")

a = array( true, false, true, true, false, false, true, false)
b = gnomeSort( a )
wscript.echo join(a, ", ")

a = array( 1,2,2,4,67789,-3,-45.99)
b = gnomeSort( a )
wscript.echo join(a, ", ")

a = array( now(), now()-1,now()+2)
b = gnomeSort( a )
wscript.echo join(a, ", ")

Output

aardvark, ampicillin, gogodala, wolverhampton, zanzibar, zulu
23, 89, 234, 345, 456, 456, 547, 567, 567, 568, 649, 2345, 5769
True, True, True, True, False, False, False, False
-45.99, -3, 1, 2, 2, 4, 67789
2/02/2010 10:19:51 AM, 3/02/2010 10:19:51 AM, 5/02/2010 10:19:51 AM

Note: All data in VBScript is of type Variant. Thus the code can sort many different types of data without code modification.

V (Vlang)

Translation of: go
fn main() {
mut a := [170, 45, 75, -90, -802, 24, 2, 66]
println("before: \$a")
gnome_sort(mut a)
println("after: \$a")
}

fn gnome_sort(mut a []int) {
for i, j := 1, 2; i < a.len; {
if a[i-1] > a[i] {
a[i-1], a[i] = a[i], a[i-1]
i--
if i > 0 {
continue
}
}
i = j
j++
}
}
Output:
before: [170, 45, 75, -90, -802, 24, 2, 66]
after: [-802, -90, 2, 24, 45, 66, 75, 170]

Wren

var gnomeSort = Fn.new { |a, asc|
var size = a.count
var i = 1
var j = 2
while (i < size) {
if ((asc && a[i-1] <= a[i]) || (!asc && a[i-1] >= a[i])) {
i = j
j = j + 1
} else {
var t = a[i-1]
a[i-1] = a[i]
a[i] = t
i = i - 1
if (i == 0) {
i = j
j = j + 1
}
}
}
}

var as = [ [4, 65, 2, -31, 0, 99, 2, 83, 782, 1], [7, 5, 2, 6, 1, 4, 2, 6, 3] ]

for (asc in [true, false]) {
System.print("Sorting in %(asc ? "ascending" : "descending") order:\n")
for (a in as) {
var b = (asc) ? a : a.toList
System.print("Before: %(b)")
gnomeSort.call(b, asc)
System.print("After : %(b)")
System.print()
}
}
Output:
Sorting in ascending order:

Before: [4, 65, 2, -31, 0, 99, 2, 83, 782, 1]
After : [-31, 0, 1, 2, 2, 4, 65, 83, 99, 782]

Before: [7, 5, 2, 6, 1, 4, 2, 6, 3]
After : [1, 2, 2, 3, 4, 5, 6, 6, 7]

Sorting in descending order:

Before: [-31, 0, 1, 2, 2, 4, 65, 83, 99, 782]
After : [782, 99, 83, 65, 4, 2, 2, 1, 0, -31]

Before: [1, 2, 2, 3, 4, 5, 6, 6, 7]
After : [7, 6, 6, 5, 4, 3, 2, 2, 1]

XPL0

code ChOut=8, IntOut=11;

proc GnomeSort(A(0..Size-1));   \Sort array A
int  A, Size;
int  I, J, T;
[I:= 1;
J:= 2;
while I < Size do
if A(I-1) <= A(I) then
[\ for descending sort, use >= for comparison
I:= J;
J:= J+1;
]
else
[T:= A(I-1);  A(I-1):= A(I);  A(I):= T; \swap
I:= I-1;
if I = 0 then
[I:= J;
J:= J+1;
];
];
];

int A, I;
[A:= [3, 1, 4, 1, -5, 9, 2, 6, 5, 4];
GnomeSort(A, 10);
for I:= 0 to 10-1 do [IntOut(0, A(I));  ChOut(0, ^ )];
]
Output:
-5 1 1 2 3 4 4 5 6 9

zkl

fcn gnomeSort(a){
i,j,size := 1,2,a.len();
while(i < size){
if(a[i-1] > a[i]){ // for descending sort, use < for comparison
a.swap(i-1,i);
i = i - 1;
if(i) continue;
}
i = j;
j = j + 1;
}//while
a
}
gnomeSort("This is a test".split("")).println();
Output:
L(" "," "," ","T","a","e","h","i","i","s","s","s","t","t")